diff --git a/packages/util/src/assertSingletonPackage.ts b/packages/util/src/assertSingletonPackage.ts
index 447a79c923..490e58a5ab 100644
--- a/packages/util/src/assertSingletonPackage.ts
+++ b/packages/util/src/assertSingletonPackage.ts
@@ -4,7 +4,10 @@
 
 import isUndefined from './is/undefined';
 
-interface PjsChecks {
+// eslint-disable-next-line no-undef
+type This = typeof globalThis;
+
+interface PjsChecks extends This {
   __polkadotjs: Record<string, boolean>;
 }