diff --git a/CHANGELOG b/CHANGELOG
index 42d32e5368542388543517c1425c8cb8ac765e71..085a9f2ee75c8754eb5f5674ef230939e0a8fe2f 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -80,6 +80,7 @@ v 8.11.0 (unreleased)
   - Sensible state specific default sort order for issues and merge requests !5453 (tomb0y)
   - Fix RequestProfiler::Middleware error when code is reloaded in development
   - Catch what warden might throw when profiling requests to re-throw it
+  - Avoid commit lookup on diff_helper passing existing local variable to the helper method
   - Add description to new_issue email and new_merge_request_email in text/plain content type. !5663 (dixpac)
   - Speed up and reduce memory usage of Commit#repo_changes, Repository#expire_avatar_cache and IrkerWorker
   - Add unfold links for Side-by-Side view. !5415 (Tim Masliuchenko)
diff --git a/app/helpers/diff_helper.rb b/app/helpers/diff_helper.rb
index f3c9ea074b470da1d1b6c2e68aa7ec9c5bfe66f7..0725c3f4c56c812256d6021e3cb9978972e11633 100644
--- a/app/helpers/diff_helper.rb
+++ b/app/helpers/diff_helper.rb
@@ -109,11 +109,10 @@ module DiffHelper
     end
   end
 
-  def diff_file_html_data(project, diff_file)
-    commit = commit_for_diff(diff_file)
+  def diff_file_html_data(project, diff_file_path, diff_commit_id)
     {
       blob_diff_path: namespace_project_blob_diff_path(project.namespace, project,
-                                                       tree_join(commit.id, diff_file.file_path)),
+                                                       tree_join(diff_commit_id, diff_file_path)),
       view: diff_view
     }
   end
diff --git a/app/views/projects/diffs/_file.html.haml b/app/views/projects/diffs/_file.html.haml
index f0a86fd6d40e054c49d45137172c422c58cdbb41..8fbd89100ca5e23c1bd42d4dde9f5f92e5957972 100644
--- a/app/views/projects/diffs/_file.html.haml
+++ b/app/views/projects/diffs/_file.html.haml
@@ -1,4 +1,4 @@
-.diff-file.file-holder{id: "diff-#{index}", data: diff_file_html_data(project, diff_file)}
+.diff-file.file-holder{id: "diff-#{index}", data: diff_file_html_data(project, diff_file.file_path, diff_commit.id)}
   .file-title{id: "file-path-#{hexdigest(diff_file.file_path)}"}
     = render "projects/diffs/file_header", diff_file: diff_file, blob: blob, diff_commit: diff_commit, project: project, url: "#diff-#{index}"