diff --git a/lib/typeorm-core.module.ts b/lib/typeorm-core.module.ts
index 05095c1b4..e59d1966f 100644
--- a/lib/typeorm-core.module.ts
+++ b/lib/typeorm-core.module.ts
@@ -217,7 +217,10 @@ export class TypeOrmCoreModule implements OnApplicationShutdown {
           const dataSource = await createTypeormDataSource(
             options as DataSourceOptions,
           );
-          return dataSource.initialize && !dataSource.isInitialized ? dataSource.initialize() : dataSource;
+          // TODO: remove "dataSource.initialize" condition (left for backward compatibility)
+          return (dataSource as any).initialize && !dataSource.isInitialized
+            ? dataSource.initialize()
+            : dataSource;
         }
 
         let entities = options.entities;
@@ -233,7 +236,11 @@ export class TypeOrmCoreModule implements OnApplicationShutdown {
           ...options,
           entities,
         } as DataSourceOptions);
-        return dataSource.initialize && !dataSource.isInitialized ? dataSource.initialize() : dataSource;
+
+        // TODO: remove "dataSource.initialize" condition (left for backward compatibility)
+        return (dataSource as any).initialize && !dataSource.isInitialized
+          ? dataSource.initialize()
+          : dataSource;
       }).pipe(
         handleRetry(
           options.retryAttempts,