diff --git a/docs/pages/api/speed-dial-action.md b/docs/pages/api/speed-dial-action.md
index f9b5ca5ed4254b..31e1902a2b8e91 100644
--- a/docs/pages/api/speed-dial-action.md
+++ b/docs/pages/api/speed-dial-action.md
@@ -26,7 +26,7 @@ You can learn more about the difference by [reading this guide](/guides/minimizi
 |:-----|:-----|:--------|:------------|
 | <span class="prop-name">classes</span> | <span class="prop-type">object</span> |  | Override or extend the styles applied to the component. See [CSS API](#css) below for more details. |
 | <span class="prop-name">delay</span> | <span class="prop-type">number</span> | <span class="prop-default">0</span> | Adds a transition delay, to allow a series of SpeedDialActions to be animated. |
-| <span class="prop-name">FabProps</span> | <span class="prop-type">object</span> |  | Props applied to the [`Fab`](/api/fab/) component. |
+| <span class="prop-name">FabProps</span> | <span class="prop-type">object</span> | <span class="prop-default">{}</span> | Props applied to the [`Fab`](/api/fab/) component. |
 | <span class="prop-name">icon</span> | <span class="prop-type">node</span> |  | The Icon to display in the SpeedDial Fab. |
 | <span class="prop-name">TooltipClasses</span> | <span class="prop-type">object</span> |  | Classes applied to the [`Tooltip`](/api/tooltip/) element. |
 | <span class="prop-name">tooltipOpen</span> | <span class="prop-type">bool</span> | <span class="prop-default">false</span> | Make the tooltip always visible when the SpeedDial is open. |
diff --git a/packages/material-ui-lab/src/SpeedDialAction/SpeedDialAction.js b/packages/material-ui-lab/src/SpeedDialAction/SpeedDialAction.js
index 545d82adb5d079..af89b88559eac3 100644
--- a/packages/material-ui-lab/src/SpeedDialAction/SpeedDialAction.js
+++ b/packages/material-ui-lab/src/SpeedDialAction/SpeedDialAction.js
@@ -80,7 +80,7 @@ const SpeedDialAction = React.forwardRef(function SpeedDialAction(props, ref) {
     classes,
     className,
     delay = 0,
-    FabProps,
+    FabProps = {},
     icon,
     id,
     open,
@@ -103,19 +103,18 @@ const SpeedDialAction = React.forwardRef(function SpeedDialAction(props, ref) {
 
   const transitionStyle = { transitionDelay: `${delay}ms` };
 
-  if (FabProps && FabProps.style) {
-    FabProps.style.transitionDelay = `${delay}ms`;
-  }
-
   const fab = (
     <Fab
       size="small"
       className={clsx(classes.fab, !open && classes.fabClosed, className)}
       tabIndex={-1}
       role="menuitem"
-      style={transitionStyle}
       aria-describedby={`${id}-label`}
       {...FabProps}
+      style={{
+        ...transitionStyle,
+        ...FabProps.style,
+      }}
     >
       {icon}
     </Fab>