diff --git a/css-paint-api/Overview.bs b/css-paint-api/Overview.bs
index f43ffc38..f7570b54 100644
--- a/css-paint-api/Overview.bs
+++ b/css-paint-api/Overview.bs
@@ -90,7 +90,7 @@ identical to the Window.{{Window/devicePixelRatio}} property.
 <pre class='idl'>
 [Global=(Worklet,PaintWorklet),Exposed=PaintWorklet]
 interface PaintWorkletGlobalScope : WorkletGlobalScope {
-    void registerPaint(DOMString name, VoidFunction paintCtor);
+    undefined registerPaint(DOMString name, VoidFunction paintCtor);
     readonly attribute unrestricted double devicePixelRatio;
 };
 </pre>