diff --git a/.github/workflows/clang-format-checker.yml b/.github/workflows/clang-format-checker.yml
index 5a29a6d5f3..1f48412385 100644
--- a/.github/workflows/clang-format-checker.yml
+++ b/.github/workflows/clang-format-checker.yml
@@ -25,7 +25,8 @@ jobs:
           GH_TOKEN: ${{ github.token }}
         run: |
             echo Comparing $GITHUB_BASE_REF vs HEAD
-            git diff -U0 --no-color origin/$GITHUB_BASE_REF..HEAD | clang-format-diff -p1 | tee format.diff
+            git fetch origin refs/pull/$PR_NUMBER/head
+            git diff -U0 --no-color origin/$GITHUB_BASE_REF..refs/pull/$PR_NUMBER/head | clang-format-diff -p1 | tee format.diff
             if [ -s "format.diff" ]
             then
               echo PR contains clang-format violations. First 50 lines of the diff: >> message.txt