diff --git a/app/models/concerns/mentionable.rb b/app/models/concerns/mentionable.rb
index 298d0d42d90..0d88b34fb48 100644
--- a/app/models/concerns/mentionable.rb
+++ b/app/models/concerns/mentionable.rb
@@ -97,9 +97,9 @@ module Mentionable
   # Allows heavy processing to be skipped
   def matches_cross_reference_regex?
     reference_pattern = if !project || project.default_issues_tracker?
-                          ReferenceRegexes::DEFAULT_PATTERN
+                          ReferenceRegexes.default_pattern
                         else
-                          ReferenceRegexes::EXTERNAL_PATTERN
+                          ReferenceRegexes.external_pattern
                         end
 
     self.class.mentionable_attrs.any? do |attr, _|
diff --git a/app/models/concerns/mentionable/reference_regexes.rb b/app/models/concerns/mentionable/reference_regexes.rb
index fe8fbb71184..b8fb3f71925 100644
--- a/app/models/concerns/mentionable/reference_regexes.rb
+++ b/app/models/concerns/mentionable/reference_regexes.rb
@@ -2,6 +2,8 @@
 
 module Mentionable
   module ReferenceRegexes
+    extend Gitlab::Utils::StrongMemoize
+
     def self.reference_pattern(link_patterns, issue_pattern)
       Regexp.union(link_patterns,
                    issue_pattern,
@@ -15,16 +17,20 @@ module Mentionable
       ]
     end
 
-    DEFAULT_PATTERN = begin
-      issue_pattern = Issue.reference_pattern
-      link_patterns = Regexp.union([Issue, Commit, MergeRequest, Epic].map(&:link_reference_pattern).compact)
-      reference_pattern(link_patterns, issue_pattern)
+    def self.default_pattern
+      strong_memoize(:default_pattern) do
+        issue_pattern = Issue.reference_pattern
+        link_patterns = Regexp.union([Issue, Commit, MergeRequest, Epic].map(&:link_reference_pattern).compact)
+        reference_pattern(link_patterns, issue_pattern)
+      end
     end
 
-    EXTERNAL_PATTERN = begin
-      issue_pattern = IssueTrackerService.reference_pattern
-      link_patterns = URI.regexp(%w(http https))
-      reference_pattern(link_patterns, issue_pattern)
+    def self.external_pattern
+      strong_memoize(:external_pattern) do
+        issue_pattern = IssueTrackerService.reference_pattern
+        link_patterns = URI.regexp(%w(http https))
+        reference_pattern(link_patterns, issue_pattern)
+      end
     end
   end
 end
diff --git a/app/models/project_services/issue_tracker_service.rb b/app/models/project_services/issue_tracker_service.rb
index a399982e5ec..f54497fc6d8 100644
--- a/app/models/project_services/issue_tracker_service.rb
+++ b/app/models/project_services/issue_tracker_service.rb
@@ -9,7 +9,7 @@ class IssueTrackerService < Service
   # Override this method on services that uses different patterns
   # This pattern does not support cross-project references
   # The other code assumes that this pattern is a superset of all
-  # overridden patterns. See ReferenceRegexes::EXTERNAL_PATTERN
+  # overridden patterns. See ReferenceRegexes.external_pattern
   def self.reference_pattern(only_long: false)
     if only_long
       /(\b[A-Z][A-Z0-9_]*-)(?<issue>\d+)/