diff --git a/material-ui/material-ui.d.ts b/material-ui/material-ui.d.ts
index 2913c0bd57..3f2894a9b6 100644
--- a/material-ui/material-ui.d.ts
+++ b/material-ui/material-ui.d.ts
@@ -536,7 +536,7 @@ declare namespace __MaterialUI {
         type horizontal = 'left' | 'middle' | 'right';
         type vertical = 'top' | 'center' | 'bottom';
         type direction = 'left' | 'right' | 'up' | 'down';
-        
+
         interface origin {
             horizontal: horizontal;
             vertical: vertical;
@@ -745,7 +745,7 @@ declare namespace __MaterialUI {
         onMouseLeave?: React.MouseEventHandler;
         onMouseOut?: React.MouseEventHandler;
         style?: React.CSSProperties;
-        tooltip?: string;
+        tooltip?: React.ReactNode | string;
         tooltipPosition?: propTypes.cornersAndCenter;
         tooltipStyles?: React.CSSProperties;
         touch?: boolean;