diff --git a/diff-sha.sh b/diff-sha.sh
index af1180b1..5daf90c8 100644
--- a/diff-sha.sh
+++ b/diff-sha.sh
@@ -56,7 +56,7 @@ if [[ -z $GITHUB_BASE_REF ]]; then
     if [[ -z $INPUT_SHA ]]; then
       CURRENT_SHA=$(git rev-list -n 1 HEAD 2>&1) && exit_status=$? || exit_status=$?
     else
-      git fetch --no-tags -u --progress --depth="$INPUT_FETCH_DEPTH" "$CURRENT_BRANCH":"$CURRENT_BRANCH"
+      git fetch --no-tags -u --progress --depth="$INPUT_FETCH_DEPTH" origin "$CURRENT_BRANCH":"$CURRENT_BRANCH"
       CURRENT_SHA=$INPUT_SHA; exit_status=$?
     fi
   fi
@@ -82,7 +82,7 @@ if [[ -z $GITHUB_BASE_REF ]]; then
         exit 1
       fi
     else
-      git fetch --no-tags -u --progress --depth="$INPUT_FETCH_DEPTH" "$CURRENT_BRANCH":"$CURRENT_BRANCH"
+      git fetch --no-tags -u --progress --depth="$INPUT_FETCH_DEPTH" origin "$CURRENT_BRANCH":"$CURRENT_BRANCH"
       PREVIOUS_SHA=$(git rev-list -n 1 "$TARGET_BRANCH" 2>&1) && exit_status=$? || exit_status=$?
       
       if [[ -z "$PREVIOUS_SHA" ]]; then
@@ -114,7 +114,7 @@ if [[ -z $GITHUB_BASE_REF ]]; then
     PREVIOUS_SHA=$INPUT_BASE_SHA
     TARGET_BRANCH=$(git name-rev --name-only "$PREVIOUS_SHA" 2>&1) && exit_status=$? || exit_status=$?
     CURRENT_BRANCH=$TARGET_BRANCH
-    git fetch --no-tags -u --progress --depth="$INPUT_FETCH_DEPTH" "$CURRENT_BRANCH":"$CURRENT_BRANCH"
+    git fetch --no-tags -u --progress --depth="$INPUT_FETCH_DEPTH" origin "$CURRENT_BRANCH":"$CURRENT_BRANCH"
   fi
 
   echo "::debug::Target branch $TARGET_BRANCH..."