diff --git a/CHANGELOG b/CHANGELOG
index d9abb322f30cbed553eb3cbcf2099f98486371e9..72679b89d82f050f07fca846a7802197781a2096 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -13,6 +13,7 @@ v 8.9.0 (unreleased)
   - Fix endless redirections when accessing user OAuth applications when they are disabled
   - Allow enabling wiki page events from Webhook management UI
   - Bump rouge to 1.11.0
+  - Fix MR-auto-close text added to description
   - Fix issue with arrow keys not working in search autocomplete dropdown
   - Fix an issue where note polling stopped working if a window was in the
     background during a refresh.
diff --git a/app/services/merge_requests/build_service.rb b/app/services/merge_requests/build_service.rb
index 1b48899bb0a0f8fdb7465a1bad40579ca9834b8c..7fe57747265156320a76b5b4ac84c1b7cd28f19b 100644
--- a/app/services/merge_requests/build_service.rb
+++ b/app/services/merge_requests/build_service.rb
@@ -83,7 +83,7 @@ module MergeRequests
         closes_issue = "Closes ##{iid}"
 
         if merge_request.description.present?
-          merge_request.description << closes_issue.prepend("\n")
+          merge_request.description += closes_issue.prepend("\n")
         else
           merge_request.description = closes_issue
         end