diff --git a/index.ts b/index.ts
index ef6ed44..c046f77 100644
--- a/index.ts
+++ b/index.ts
@@ -1,5 +1,5 @@
 import * as pathlib from 'path';
-import { Stack, Duration, Arn } from 'aws-cdk-lib';
+import { Duration, Arn } from 'aws-cdk-lib';
 import * as ecs from 'aws-cdk-lib/aws-ecs';
 import * as events from 'aws-cdk-lib/aws-events';
 import * as eventsTargets from 'aws-cdk-lib/aws-events-targets';
@@ -13,7 +13,6 @@ export interface MutableTagEcsUpdaterProps {
     ecsService: ecs.IBaseService;
     pullSecret: secretsmanager.ISecret;
     autoUpdateRate?: string;
-    clusterStack?: Stack;
 }
 
 export class MutableTagEcsUpdater extends Construct {
@@ -52,19 +51,22 @@ export class MutableTagEcsUpdater extends Construct {
                 resources: ['*'],
             }),
         );
+
+        const clusterArnParts = Arn.parse(props.ecsCluster.clusterArn);
+        const clusterTasksArn = Arn.format(
+            {
+                ...clusterArnParts,
+                resource: 'task',
+                resourceName: `${clusterArnParts.resourceName}/*`,
+            },
+        );
+
         tagUpdateLambda.addToRolePolicy(
             new iam.PolicyStatement({
                 actions: ['ecs:DescribeTasks'],
                 resources: [
                     `${props.ecsService.serviceArn}/*`,
-                    Arn.format(
-                        {
-                            resource: 'task',
-                            service: 'ecs',
-                            resourceName: `${props.ecsCluster.clusterName}/*`,
-                        },
-                        props.clusterStack,
-                    ),
+                    clusterTasksArn,
                 ],
             }),
         );