diff --git a/packages/react-reconciler/src/ReactFiberCommitWork.new.js b/packages/react-reconciler/src/ReactFiberCommitWork.new.js
index 7e489ccfe74ba..e0bd907706f61 100644
--- a/packages/react-reconciler/src/ReactFiberCommitWork.new.js
+++ b/packages/react-reconciler/src/ReactFiberCommitWork.new.js
@@ -52,6 +52,7 @@ import {
   enableUseEventHook,
   enableStrictEffects,
   enableFloat,
+  enableLegacyHidden,
 } from 'shared/ReactFeatureFlags';
 import {
   FunctionComponent,
@@ -3419,7 +3420,23 @@ function commitPassiveMountOnFiber(
       }
       break;
     }
-    case LegacyHiddenComponent:
+    case LegacyHiddenComponent: {
+      if (enableLegacyHidden) {
+        recursivelyTraversePassiveMountEffects(
+          finishedRoot,
+          finishedWork,
+          committedLanes,
+          committedTransitions,
+        );
+
+        if (flags & Passive) {
+          const current = finishedWork.alternate;
+          const instance: OffscreenInstance = finishedWork.stateNode;
+          commitOffscreenPassiveMountEffects(current, finishedWork, instance);
+        }
+      }
+      break;
+    }
     case OffscreenComponent: {
       // TODO: Pass `current` as argument to this function
       const instance: OffscreenInstance = finishedWork.stateNode;
@@ -3600,7 +3617,25 @@ export function reconnectPassiveEffects(
     // case HostRoot: {
     //  ...
     // }
-    case LegacyHiddenComponent:
+    case LegacyHiddenComponent: {
+      if (enableLegacyHidden) {
+        recursivelyTraverseReconnectPassiveEffects(
+          finishedRoot,
+          finishedWork,
+          committedLanes,
+          committedTransitions,
+          includeWorkInProgressEffects,
+        );
+
+        if (includeWorkInProgressEffects && flags & Passive) {
+          // TODO: Pass `current` as argument to this function
+          const current: Fiber | null = finishedWork.alternate;
+          const instance: OffscreenInstance = finishedWork.stateNode;
+          commitOffscreenPassiveMountEffects(current, finishedWork, instance);
+        }
+      }
+      break;
+    }
     case OffscreenComponent: {
       const instance: OffscreenInstance = finishedWork.stateNode;
       const nextState: OffscreenState | null = finishedWork.memoizedState;
diff --git a/packages/react-reconciler/src/ReactFiberCommitWork.old.js b/packages/react-reconciler/src/ReactFiberCommitWork.old.js
index 4957356c30383..0f449a81dc836 100644
--- a/packages/react-reconciler/src/ReactFiberCommitWork.old.js
+++ b/packages/react-reconciler/src/ReactFiberCommitWork.old.js
@@ -52,6 +52,7 @@ import {
   enableUseEventHook,
   enableStrictEffects,
   enableFloat,
+  enableLegacyHidden,
 } from 'shared/ReactFeatureFlags';
 import {
   FunctionComponent,
@@ -3419,7 +3420,23 @@ function commitPassiveMountOnFiber(
       }
       break;
     }
-    case LegacyHiddenComponent:
+    case LegacyHiddenComponent: {
+      if (enableLegacyHidden) {
+        recursivelyTraversePassiveMountEffects(
+          finishedRoot,
+          finishedWork,
+          committedLanes,
+          committedTransitions,
+        );
+
+        if (flags & Passive) {
+          const current = finishedWork.alternate;
+          const instance: OffscreenInstance = finishedWork.stateNode;
+          commitOffscreenPassiveMountEffects(current, finishedWork, instance);
+        }
+      }
+      break;
+    }
     case OffscreenComponent: {
       // TODO: Pass `current` as argument to this function
       const instance: OffscreenInstance = finishedWork.stateNode;
@@ -3600,7 +3617,25 @@ export function reconnectPassiveEffects(
     // case HostRoot: {
     //  ...
     // }
-    case LegacyHiddenComponent:
+    case LegacyHiddenComponent: {
+      if (enableLegacyHidden) {
+        recursivelyTraverseReconnectPassiveEffects(
+          finishedRoot,
+          finishedWork,
+          committedLanes,
+          committedTransitions,
+          includeWorkInProgressEffects,
+        );
+
+        if (includeWorkInProgressEffects && flags & Passive) {
+          // TODO: Pass `current` as argument to this function
+          const current: Fiber | null = finishedWork.alternate;
+          const instance: OffscreenInstance = finishedWork.stateNode;
+          commitOffscreenPassiveMountEffects(current, finishedWork, instance);
+        }
+      }
+      break;
+    }
     case OffscreenComponent: {
       const instance: OffscreenInstance = finishedWork.stateNode;
       const nextState: OffscreenState | null = finishedWork.memoizedState;
diff --git a/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js b/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js
index 30bbaea058995..ca505c785fe48 100644
--- a/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js
@@ -942,6 +942,62 @@ describe('ReactOffscreen', () => {
     ]);
   });
 
+  // @gate enableLegacyHidden
+  it('do not defer passive effects when prerendering a new LegacyHidden tree', async () => {
+    function Child({label}) {
+      useEffect(() => {
+        Scheduler.unstable_yieldValue('Mount ' + label);
+        return () => {
+          Scheduler.unstable_yieldValue('Unmount ' + label);
+        };
+      }, [label]);
+      return <Text text={label} />;
+    }
+
+    function App({showMore}) {
+      return (
+        <>
+          <Child label="Shell" />
+          <LegacyHidden
+            mode={showMore ? 'visible' : 'unstable-defer-without-hiding'}>
+            <Child label="More" />
+          </LegacyHidden>
+        </>
+      );
+    }
+
+    const root = ReactNoop.createRoot();
+
+    // Mount the app without showing the extra content
+    await act(async () => {
+      root.render(<App showMore={false} />);
+    });
+    expect(Scheduler).toHaveYielded([
+      // First mount the outer visible shell
+      'Shell',
+      'Mount Shell',
+
+      // Then prerender the hidden extra context. Unlike Offscreen, the passive
+      // effects in the hidden tree *should* fire
+      'More',
+      'Mount More',
+    ]);
+
+    // The hidden content has been prerendered
+    expect(root).toMatchRenderedOutput(
+      <>
+        <span prop="Shell" />
+        <span prop="More" />
+      </>,
+    );
+
+    // Reveal the prerendered tree
+    await act(async () => {
+      root.render(<App showMore={true} />);
+    });
+    expect(Scheduler).toHaveYielded(['Shell', 'More']);
+  });
+
   // @gate enableOffscreen
   it('passive effects are connected and disconnected when the visibility changes', async () => {
     function Child({step}) {