diff --git a/modules/data/src/entity-services/entity-collection-service-base.ts b/modules/data/src/entity-services/entity-collection-service-base.ts
index 31069ba2bd..7b4ef08fdd 100644
--- a/modules/data/src/entity-services/entity-collection-service-base.ts
+++ b/modules/data/src/entity-services/entity-collection-service-base.ts
@@ -145,10 +145,6 @@ export class EntityCollectionServiceBase<
     entity: Partial<T>,
     options: EntityActionOptions & { isOptimistic: false }
   ): Observable<T>;
-  add(
-    entity: T,
-    options?: EntityActionOptions & { isOptimistic?: true }
-  ): Observable<T>;
   add(entity: T, options?: EntityActionOptions): Observable<T> {
     return this.dispatcher.add(entity, options);
   }