diff --git a/packages/@aws-cdk/aws-codepipeline-actions/lib/codecommit/source-action.ts b/packages/@aws-cdk/aws-codepipeline-actions/lib/codecommit/source-action.ts
index 591609252ba68..8f33d16ac8c41 100644
--- a/packages/@aws-cdk/aws-codepipeline-actions/lib/codecommit/source-action.ts
+++ b/packages/@aws-cdk/aws-codepipeline-actions/lib/codecommit/source-action.ts
@@ -160,7 +160,7 @@ export class CodeCommitSourceAction extends Action {
       let candidate = '';
       let counter = 0;
       do {
-        candidate = this.eventIdFromPrefix(`${baseId}{counter}`);
+        candidate = this.eventIdFromPrefix(`${baseId}${counter}`);
         counter += 1;
       } while (this.props.repository.node.tryFindChild(candidate) !== undefined);
       return candidate;