diff --git a/action.yml b/action.yml
index a37893c1582..1c3078e8d3b 100644
--- a/action.yml
+++ b/action.yml
@@ -165,7 +165,10 @@ runs:
         elif [[ -n "${{ inputs.base_sha }}" ]]; then
           echo "::set-output name=base_sha::${{ inputs.base_sha }}"
         elif [[ "${{ inputs.since_last_remote_commit }}" == "true" ]]; then
-          LAST_REMOTE_COMMIT=$(git rev-parse $(git branch -r --sort=-committerdate | head -1))
+          LAST_REMOTE_COMMIT="${{ github.event.before }}"
+          if [[ -z "$LAST_REMOTE_COMMIT" ]]; then
+            LAST_REMOTE_COMMIT=$(git rev-parse $(git branch -r --sort=-committerdate | head -1))
+          fi
           if [[ "${{ inputs.sha }}" == "$LAST_REMOTE_COMMIT" ]]; then
             LAST_REMOTE_COMMIT=$(git rev-parse "${{ inputs.sha }}^1")
           fi