diff --git a/Bugzilla/Bug.pm b/Bugzilla/Bug.pm
index 94f1db77f..f1e256d80 100644
--- a/Bugzilla/Bug.pm
+++ b/Bugzilla/Bug.pm
@@ -3973,7 +3973,7 @@ sub get_ids
     {
         return $self->{$fn};
     }
-    elsif ($field && $field->type == FIELD_TYPE_MULTI_SELECT)
+    elsif ($field && ($field->type == FIELD_TYPE_MULTI_SELECT || $field->type == FIELD_TYPE_BUG_ID_REV))
     {
         return $self->$fn;
     }
@@ -4000,6 +4000,10 @@ sub get_object
     {
         $self->{$attr} = $field->value_type->new_from_list($self->$fn);
     }
+    elsif ($field && $field->type == FIELD_TYPE_BUG_ID_REV)
+    {
+        $self->{$attr} = Bugzilla::Bug->new_from_list($self->$fn);
+    }
     else
     {
         die "Invalid join requested - ".__PACKAGE__."::$attr";
@@ -4015,15 +4019,19 @@ sub get_string
     my $f = ref $field ? $field->name : $field;
     $field = Bugzilla->get_field($field) if !ref $field;
     my $value;
-    if ($field->type == FIELD_TYPE_SINGLE_SELECT)
+    if ($field && $field->type == FIELD_TYPE_SINGLE_SELECT)
     {
         $value = $self->get_object($f) && $self->get_object($f)->name;
     }
-    elsif ($field->type == FIELD_TYPE_MULTI_SELECT)
+    elsif ($field && $field->type == FIELD_TYPE_MULTI_SELECT)
     {
         $value = join ', ', map { $_->name } @{$self->get_object($f)};
     }
-    elsif ($field->type != FIELD_TYPE_UNKNOWN || SCALAR_FORMAT->{$f})
+    elsif ($field && $field->type == FIELD_TYPE_BUG_ID_REV)
+    {
+        $value = join ', ', @{ $self->$f };
+    }
+    elsif ($field && $field->type != FIELD_TYPE_UNKNOWN || SCALAR_FORMAT->{$f})
     {
         $value = $self->$f;
     }
@@ -4123,12 +4131,22 @@ sub AUTOLOAD
         }
 
         my $field = Bugzilla->get_field($attr);
-        if ($field && $field->type == FIELD_TYPE_MULTI_SELECT)
+        if ($field)
         {
-            $self->{$attr} ||= Bugzilla->dbh->selectcol_arrayref(
-                "SELECT id FROM bug_$attr, $attr WHERE value_id=id AND bug_id=? ORDER BY value",
-                undef, $self->id);
-            return $self->{$attr};
+            if ($field->type == FIELD_TYPE_MULTI_SELECT)
+            {
+                $self->{$attr} ||= Bugzilla->dbh->selectcol_arrayref(
+                    "SELECT id FROM bug_$attr, $attr WHERE value_id=id AND bug_id=? ORDER BY value",
+                    undef, $self->id);
+                return $self->{$attr};
+            }
+            elsif ($field->type == FIELD_TYPE_BUG_ID_REV)
+            {
+                $self->{$attr} ||= Bugzilla->dbh->selectcol_arrayref(
+                    "SELECT bug_id FROM bugs WHERE ".$field->value_field->name." = ".$self->id
+                );
+                return $self->{$attr};
+            }
         }
 
         return '';
diff --git a/Bugzilla/Constants.pm b/Bugzilla/Constants.pm
index 4440563ad..8b1419e44 100644
--- a/Bugzilla/Constants.pm
+++ b/Bugzilla/Constants.pm
@@ -130,6 +130,7 @@ use Cwd qw(abs_path);
     FIELD_TYPE_KEYWORDS
     FIELD_TYPE_NUMERIC
     FIELD_TYPE_EXTURL
+    FIELD_TYPE_BUG_ID_REV
 
     TIMETRACKING_FIELDS
 
@@ -382,6 +383,7 @@ use constant FIELD_TYPE_KEYWORDS => 8;
 
 use constant FIELD_TYPE_NUMERIC => 30;
 use constant FIELD_TYPE_EXTURL => 31;
+use constant FIELD_TYPE_BUG_ID_REV => 32;
 
 use constant BUG_ID_ADD_TO_BLOCKED => 1;
 use constant BUG_ID_ADD_TO_DEPENDSON => 2;
diff --git a/Bugzilla/Field.pm b/Bugzilla/Field.pm
index f0b8a4944..ed0dfc7ef 100644
--- a/Bugzilla/Field.pm
+++ b/Bugzilla/Field.pm
@@ -130,7 +130,7 @@ use constant VALIDATORS => {
 };
 
 use constant UPDATE_VALIDATORS => {
-    value_field_id      => \&_check_value_field_id,
+    value_field_id => \&_check_value_field_id,
 };
 
 use constant UPDATE_COLUMNS => qw(
@@ -306,7 +306,7 @@ sub _check_type
     # higher field type is added.
     if (!detaint_natural($type) || $type < FIELD_TYPE_UNKNOWN ||
         $type > FIELD_TYPE_KEYWORDS && $type < FIELD_TYPE_NUMERIC ||
-        $type > FIELD_TYPE_EXTURL)
+        $type > FIELD_TYPE_BUG_ID_REV)
     {
         ThrowCodeError('invalid_customfield_type', { type => $saved_type });
     }
@@ -315,9 +315,27 @@ sub _check_type
 
 sub _check_value_field_id
 {
-    my ($invocant, $field_id, $is_select) = @_;
-    $is_select = $invocant->is_select if !defined $is_select;
-    if ($field_id && !$is_select)
+    my ($invocant, $field_id, undef, $type) = @_;
+    $type = $invocant->type if !defined $type;
+    if ($type == FIELD_TYPE_BUG_ID_REV)
+    {
+        # For fields of type "reverse relation of BUG_ID field"
+        # value_field indicates the needed direct relation
+        my $field = Bugzilla->get_field(trim($field_id));
+        if (!$field || $field->type != FIELD_TYPE_BUG_ID)
+        {
+            ThrowUserError('direct_field_needed_for_reverse');
+        }
+        for (Bugzilla->get_fields({ type => FIELD_TYPE_BUG_ID_REV, value_field_id => $field->id }))
+        {
+            if (!ref $invocant || $_->id != $invocant->id)
+            {
+                ThrowUserError('duplicate_reverse_field');
+            }
+        }
+        return $field->id;
+    }
+    if ($field_id && $type != FIELD_TYPE_SINGLE_SELECT && $type != FIELD_TYPE_MULTI_SELECT)
     {
         ThrowUserError('field_value_control_select_only');
     }
@@ -729,7 +747,7 @@ sub value_field
 sub value_field_id
 {
     my $self = shift;
-    return undef if !$self->is_select;
+    return undef if !$self->is_select && $self->type != FIELD_TYPE_BUG_ID_REV;
     return $self->{value_field_id};
 }
 
@@ -930,7 +948,7 @@ sub update
     # FIXME Merge something like VALIDATOR_DEPENDENCIES from 4.4
     if ($self->{type} != FIELD_TYPE_BUG_ID)
     {
-        $self->{add_to_deps} = undef;
+        $self->{add_to_deps} = 0;
     }
     if ($self->{type} != FIELD_TYPE_EXTURL)
     {
@@ -1054,15 +1072,12 @@ sub run_create_validators
         ThrowCodeError('field_type_not_specified');
     }
 
-    $params->{value_field_id} = $class->_check_value_field_id(
-        $params->{value_field_id},
-        ($type == FIELD_TYPE_SINGLE_SELECT || $type == FIELD_TYPE_MULTI_SELECT) ? 1 : 0
-    );
+    $params->{value_field_id} = $class->_check_value_field_id($params->{value_field_id}, undef, $type);
 
     # FIXME Merge something like VALIDATOR_DEPENDENCIES from 4.4
     if ($type != FIELD_TYPE_BUG_ID)
     {
-        $params->{add_to_deps} = undef;
+        $params->{add_to_deps} = 0;
     }
     if ($type != FIELD_TYPE_EXTURL)
     {
diff --git a/Bugzilla/Install/DB.pm b/Bugzilla/Install/DB.pm
index 7a4d99241..a9d04e1f2 100644
--- a/Bugzilla/Install/DB.pm
+++ b/Bugzilla/Install/DB.pm
@@ -130,6 +130,7 @@ sub update_fielddefs_definition {
         $dbh->do('UPDATE fielddefs SET type='.FIELD_TYPE_EXTURL.' WHERE custom=1 AND type=9');
     }
 
+    # This column is used for fast lookup of fields used in bug history
     if (!$dbh->bz_column_info('fielddefs', 'has_activity'))
     {
         $dbh->bz_add_column('fielddefs', has_activity => {TYPE => 'BOOLEAN', NOTNULL => 1, DEFAULT => 0});
@@ -140,6 +141,26 @@ sub update_fielddefs_definition {
         );
     }
 
+    # Migrate reverse_desc (upstream implementation) into separate field objects
+    if ($dbh->bz_column_info('fielddefs', 'reverse_desc'))
+    {
+        my $rows = $dbh->selectall_arrayref(
+            'SELECT * FROM fielddefs WHERE custom=1 AND type='.FIELD_TYPE_BUG_ID.
+            ' AND reverse_desc IS NOT NULL AND reverse_desc != \'\'', {Slice=>{}}
+        );
+        for (@$rows)
+        {
+            Bugzilla::Field->create({
+                name => $_->{name}.'_rev',
+                custom => 1,
+                description => $_->{reverse_desc},
+                type => FIELD_TYPE_BUG_ID_REV,
+                value_field_id => $_->{id},
+            });
+        }
+        $dbh->bz_drop_column('fielddefs', 'reverse_desc');
+    }
+
     # Remember, this is not the function for adding general table changes.
     # That is below. Add new changes to the fielddefs table above this
     # comment.
diff --git a/Bugzilla/Language/en.pm b/Bugzilla/Language/en.pm
index 58a19652e..f5d46cd90 100644
--- a/Bugzilla/Language/en.pm
+++ b/Bugzilla/Language/en.pm
@@ -67,13 +67,14 @@ $Bugzilla::messages->{en} = {
     field_types => {
         FIELD_TYPE_UNKNOWN()       => 'Unknown Type',
         FIELD_TYPE_FREETEXT()      => 'Free Text',
-        FIELD_TYPE_EXTURL()        => 'External URL',
         FIELD_TYPE_SINGLE_SELECT() => 'Drop Down',
         FIELD_TYPE_MULTI_SELECT()  => 'Multiple-Selection Box',
         FIELD_TYPE_TEXTAREA()      => 'Large Text Box',
         FIELD_TYPE_DATETIME()      => 'Date/Time',
         FIELD_TYPE_BUG_ID()        => $terms->{Bug}.' ID',
         FIELD_TYPE_NUMERIC()       => 'Numeric',
+        FIELD_TYPE_EXTURL()        => 'External URL',
+        FIELD_TYPE_BUG_ID_REV()    => $terms->{Bug}.' ID reverse',
     },
     control_options => {
         CONTROLMAPNA() => 'NA',
diff --git a/js/cf-edit.js b/js/cf-edit.js
index 76238d869..2ef21d2ec 100644
--- a/js/cf-edit.js
+++ b/js/cf-edit.js
@@ -6,11 +6,30 @@ function onChangeType()
 {
   var type_field = document.getElementById('type');
   var value_field = document.getElementById('value_field_id');
-  if (type_field.value == constants.FIELD_TYPE_SINGLE_SELECT
-      || type_field.value == constants.FIELD_TYPE_MULTI_SELECT)
+  if (type_field.value == constants.FIELD_TYPE_SINGLE_SELECT ||
+    type_field.value == constants.FIELD_TYPE_MULTI_SELECT)
+  {
     value_field.disabled = false;
+    document.getElementById('value_field_row').style.display = '';
+  }
   else
+  {
     value_field.disabled = true;
+    document.getElementById('value_field_row').style.display = 'none';
+  }
+  var rev_value_field = document.getElementById('bug_id_rev_value_field_id');
+  if (type_field.value == constants.FIELD_TYPE_BUG_ID_REV)
+  {
+    rev_value_field.name = 'value_field_id';
+    value_field.name = '';
+    document.getElementById('bug_id_rev_row').style.display = '';
+  }
+  else
+  {
+    rev_value_field.name = '';
+    value_field.name = 'value_field_id';
+    document.getElementById('bug_id_rev_row').style.display = 'none';
+  }
   document.getElementById('add_to_deps').style.display
     = document.getElementById('add_to_deps_title').style.display
     = type_field.value == constants.FIELD_TYPE_BUG_ID ? '' : 'none';
diff --git a/template/en/default/admin/custom_fields/edit.html.tmpl b/template/en/default/admin/custom_fields/edit.html.tmpl
index 00d4fc315..83b558815 100644
--- a/template/en/default/admin/custom_fields/edit.html.tmpl
+++ b/template/en/default/admin/custom_fields/edit.html.tmpl
@@ -30,7 +30,8 @@ var constants = {
   FIELD_TYPE_SINGLE_SELECT: [% constants.FIELD_TYPE_SINGLE_SELECT %],
   FIELD_TYPE_MULTI_SELECT: [% constants.FIELD_TYPE_MULTI_SELECT %],
   FIELD_TYPE_BUG_ID: [% constants.FIELD_TYPE_BUG_ID %],
-  FIELD_TYPE_EXTURL: [% constants.FIELD_TYPE_EXTURL %]
+  FIELD_TYPE_EXTURL: [% constants.FIELD_TYPE_EXTURL %],
+  FIELD_TYPE_BUG_ID_REV: [% constants.FIELD_TYPE_BUG_ID_REV %]
 };
 [% END %]
 
@@ -108,7 +109,7 @@ var constants = {
           [% field_types.${field.type} | html %]
         [% ELSE %]
           <select id="type" name="type" onchange="onChangeType()">
-            [% FOREACH type = field_types.keys %]
+            [% FOREACH type = field_types.sort %]
               [% NEXT IF type == constants.FIELD_TYPE_UNKNOWN %]
               <option value="[% type | html %]">[% field_types.$type | html %]</option>
             [% END %]
@@ -183,7 +184,7 @@ var constants = {
     </tr>
     [% END %]
     [% IF field.is_select || !field.id %]
-    <tr valign="top">
+    <tr valign="top" id="value_field_row">
       <th colspan="2" align="left"><label for="value_field_id">
         Field that controls the values that appear in this field:
       </label></th>
@@ -202,6 +203,27 @@ var constants = {
       </td>
     </tr>
     [% END %]
+    [% IF field.type == constants.FIELD_TYPE_BUG_ID_REV || !field.id %]
+    <tr valign="top" id="bug_id_rev_row">
+      <th colspan="2" align="left"><label for="bug_id_rev_value_field_id">
+        Direct Bug ID field for this reverse one:
+      </label></th>
+      <td colspan="2">
+        [%# Duplicate name will be cleared by JS on creation form %]
+        <select style="width: 400px" name="value_field_id" id="bug_id_rev_value_field_id">
+          <option value="">---</option>
+          [% FOREACH sel_field = Bugzilla.get_fields({ custom => 1, type => constants.FIELD_TYPE_BUG_ID }) %]
+            [% NEXT IF sel_field.id == field.id %]
+            <option value="[% sel_field.id | html %]"
+              [% ' selected="selected"' IF sel_field.id == field.value_field.id %]>
+              [% sel_field.description | html %]
+              ([% sel_field.name | html %])
+            </option>
+          [% END %]
+        </select>
+      </td>
+    </tr>
+    [% END %]
     [% IF field.visibility_field %]
     <tr valign="top" id="visibility_value_row">
       <th colspan="2" align="left"><label for="visibility_value_id">
diff --git a/template/en/default/global/user-error.html.tmpl b/template/en/default/global/user-error.html.tmpl
index 80c858233..9ac7680e1 100644
--- a/template/en/default/global/user-error.html.tmpl
+++ b/template/en/default/global/user-error.html.tmpl
@@ -544,6 +544,20 @@
   is not the right type of field.
 [% END %]
 
+[% BLOCK error_direct_field_needed_for_reverse %]
+  [% title = "Invalid Direct Field selected" %]
+  Each field of type "[% lc_messages.field_types.${constants.FIELD_TYPE_BUG_ID_REV} %]" must correspond
+  to one, and only one field of type "[% lc_messages.field_types.${constants.FIELD_TYPE_BUG_ID} %]" and
+  represent its "reverse relation". For example, it may be "Internal Bugs" for the corresponding
+  "External Bug" field.
+[% END %]
+
+[% BLOCK error_duplicate_reverse_field %]
+  [% title = "Duplicate Reverse Field" %]
+  It is prohibited to create more than one field of type "[% lc_messages.field_types.${constants.FIELD_TYPE_BUG_ID_REV} %]"
+  corresponding to a single "[% lc_messages.field_types.${constants.FIELD_TYPE_BUG_ID} %]" type field.
+[% END %]
+
 [% BLOCK error_field_type_mismatch %]
   Cannot seem to handle <code>[% field FILTER html %]</code>
   and <code>[% type FILTER html %]</code> together.