diff --git a/packages/material-ui/src/styles/createPalette.d.ts b/packages/material-ui/src/styles/createPalette.d.ts
index 887791ae668fa0..8d07c28f92273f 100644
--- a/packages/material-ui/src/styles/createPalette.d.ts
+++ b/packages/material-ui/src/styles/createPalette.d.ts
@@ -11,6 +11,7 @@ interface TypeText {
 interface TypeAction {
   active: string;
   hover: string;
+  hoverOpacity: number;
   selected: string;
   disabled: string;
   disabledBackground: string;