diff --git a/packages/cdktf/lib/tokens/string-fragments.ts b/packages/cdktf/lib/tokens/string-fragments.ts
index a0a5369889..bfaf03ccc5 100644
--- a/packages/cdktf/lib/tokens/string-fragments.ts
+++ b/packages/cdktf/lib/tokens/string-fragments.ts
@@ -87,7 +87,7 @@ export class TokenizedStringFragments {
   }
 
   public concat(other: TokenizedStringFragments): void {
-    this.fragments.concat(other.fragments);
+    this.fragments.push(...other.fragments);
   }
 
   /**