diff --git a/packages/charm/src/index.d.ts b/packages/charm/src/index.d.ts
index 132a5be..c709f81 100644
--- a/packages/charm/src/index.d.ts
+++ b/packages/charm/src/index.d.ts
@@ -76,7 +76,7 @@ export function signal<T>(
 	equals?: Equals<T>,
 ): LuaTuple<[getter: () => T, setter: (newValue: T | ((currentValue: T) => T)) => T]>;
 export function signal<T>(): LuaTuple<
-	[getter: () => T | undefined, setter: (newValue: T | ((currentValue?: T) => T | undefined)) => T | undefined]
+	[getter: () => T | undefined, setter: (newValue: T | undefined | ((currentValue?: T) => T | undefined)) => T | undefined]
 >;
 
 /**