diff --git a/packages/react-native-renderer/src/ReactNativeAttributePayloadFabric.js b/packages/react-native-renderer/src/ReactNativeAttributePayloadFabric.js
index f97c31e3980b6..8b8e45e7514f1 100644
--- a/packages/react-native-renderer/src/ReactNativeAttributePayloadFabric.js
+++ b/packages/react-native-renderer/src/ReactNativeAttributePayloadFabric.js
@@ -14,7 +14,10 @@ import {
 } from 'react-native/Libraries/ReactPrivate/ReactNativePrivateInterface';
 import isArray from 'shared/isArray';
 
-import {enableShallowPropDiffing} from 'shared/ReactFeatureFlags';
+import {
+  enableShallowPropDiffing,
+  enableFastAddPropertiesInDiffing,
+} from 'shared/ReactFeatureFlags';
 
 import type {AttributeConfiguration} from './ReactNativeTypes';
 
@@ -218,7 +221,11 @@ function addNestedProperty(
 
   if (!isArray(nextProp)) {
     // Add each property of the leaf.
-    return addProperties(updatePayload, nextProp, validAttributes);
+    if (enableFastAddPropertiesInDiffing) {
+      return fastAddProperties(updatePayload, nextProp, validAttributes);
+    } else {
+      return addProperties(updatePayload, nextProp, validAttributes);
+    }
   }
 
   for (let i = 0; i < nextProp.length; i++) {
diff --git a/packages/shared/ReactFeatureFlags.js b/packages/shared/ReactFeatureFlags.js
index 6a77c29ff32e2..a94f3402de4f8 100644
--- a/packages/shared/ReactFeatureFlags.js
+++ b/packages/shared/ReactFeatureFlags.js
@@ -157,6 +157,8 @@ export const enableInfiniteRenderLoopDetection = false;
  */
 export const enableUseResourceEffectHook = false;
 
+export const enableFastAddPropertiesInDiffing = true;
+
 // -----------------------------------------------------------------------------
 // Ready for next major.
 //
diff --git a/packages/shared/forks/ReactFeatureFlags.native-fb-dynamic.js b/packages/shared/forks/ReactFeatureFlags.native-fb-dynamic.js
index b6e3b098dbb40..cff57d26ecd95 100644
--- a/packages/shared/forks/ReactFeatureFlags.native-fb-dynamic.js
+++ b/packages/shared/forks/ReactFeatureFlags.native-fb-dynamic.js
@@ -28,3 +28,4 @@ export const enableSiblingPrerendering = __VARIANT__;
 export const enableUseResourceEffectHook = __VARIANT__;
 export const enableOwnerStacks = __VARIANT__;
 export const enableRemoveConsolePatches = __VARIANT__;
+export const enableFastAddPropertiesInDiffing = __VARIANT__;
diff --git a/packages/shared/forks/ReactFeatureFlags.native-fb.js b/packages/shared/forks/ReactFeatureFlags.native-fb.js
index c1d23e898ca83..31b3333966410 100644
--- a/packages/shared/forks/ReactFeatureFlags.native-fb.js
+++ b/packages/shared/forks/ReactFeatureFlags.native-fb.js
@@ -30,6 +30,7 @@ export const {
   enableSiblingPrerendering,
   enableOwnerStacks,
   enableRemoveConsolePatches,
+  enableFastAddPropertiesInDiffing,
 } = dynamicFlags;
 
 // The rest of the flags are static for better dead code elimination.
diff --git a/packages/shared/forks/ReactFeatureFlags.native-oss.js b/packages/shared/forks/ReactFeatureFlags.native-oss.js
index afe18430eba9d..84307ce62746c 100644
--- a/packages/shared/forks/ReactFeatureFlags.native-oss.js
+++ b/packages/shared/forks/ReactFeatureFlags.native-oss.js
@@ -72,6 +72,7 @@ export const enableYieldingBeforePassive = false;
 
 export const enableThrottledScheduling = false;
 export const enableViewTransition = false;
+export const enableFastAddPropertiesInDiffing = false;
 
 // Profiling Only
 export const enableProfilerTimer = __PROFILE__;
diff --git a/packages/shared/forks/ReactFeatureFlags.test-renderer.js b/packages/shared/forks/ReactFeatureFlags.test-renderer.js
index 5b4c33f331231..90725f666e1a1 100644
--- a/packages/shared/forks/ReactFeatureFlags.test-renderer.js
+++ b/packages/shared/forks/ReactFeatureFlags.test-renderer.js
@@ -71,6 +71,7 @@ export const enableYieldingBeforePassive = true;
 
 export const enableThrottledScheduling = false;
 export const enableViewTransition = false;
+export const enableFastAddPropertiesInDiffing = true;
 
 // TODO: This must be in sync with the main ReactFeatureFlags file because
 // the Test Renderer's value must be the same as the one used by the
diff --git a/packages/shared/forks/ReactFeatureFlags.test-renderer.native-fb.js b/packages/shared/forks/ReactFeatureFlags.test-renderer.native-fb.js
index ebc8c5eb97796..b4df6f248f9fd 100644
--- a/packages/shared/forks/ReactFeatureFlags.test-renderer.native-fb.js
+++ b/packages/shared/forks/ReactFeatureFlags.test-renderer.native-fb.js
@@ -69,6 +69,7 @@ export const enableYieldingBeforePassive = false;
 export const enableThrottledScheduling = false;
 export const enableViewTransition = false;
 export const enableRemoveConsolePatches = false;
+export const enableFastAddPropertiesInDiffing = false;
 
 // Flow magic to verify the exports of this file match the original version.
 ((((null: any): ExportsType): FeatureFlagsType): ExportsType);
diff --git a/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js b/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js
index c7c0e627305f0..a09e479f1732b 100644
--- a/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js
+++ b/packages/shared/forks/ReactFeatureFlags.test-renderer.www.js
@@ -84,6 +84,7 @@ export const enableYieldingBeforePassive = false;
 export const enableThrottledScheduling = false;
 export const enableViewTransition = false;
 export const enableRemoveConsolePatches = false;
+export const enableFastAddPropertiesInDiffing = false;
 
 // Flow magic to verify the exports of this file match the original version.
 ((((null: any): ExportsType): FeatureFlagsType): ExportsType);
diff --git a/packages/shared/forks/ReactFeatureFlags.www-dynamic.js b/packages/shared/forks/ReactFeatureFlags.www-dynamic.js
index b75a0a91756e1..ca097b5a9efa0 100644
--- a/packages/shared/forks/ReactFeatureFlags.www-dynamic.js
+++ b/packages/shared/forks/ReactFeatureFlags.www-dynamic.js
@@ -38,6 +38,7 @@ export const enableSiblingPrerendering = __VARIANT__;
 
 export const enableUseResourceEffectHook = __VARIANT__;
 export const enableRemoveConsolePatches = __VARIANT__;
+export const enableFastAddPropertiesInDiffing = __VARIANT__;
 
 // TODO: These flags are hard-coded to the default values used in open source.
 // Update the tests so that they pass in either mode, then set these
diff --git a/packages/shared/forks/ReactFeatureFlags.www.js b/packages/shared/forks/ReactFeatureFlags.www.js
index 58a7bcd26f9d6..223872618e603 100644
--- a/packages/shared/forks/ReactFeatureFlags.www.js
+++ b/packages/shared/forks/ReactFeatureFlags.www.js
@@ -37,6 +37,7 @@ export const {
   transitionLaneExpirationMs,
   enableOwnerStacks,
   enableRemoveConsolePatches,
+  enableFastAddPropertiesInDiffing,
 } = dynamicFeatureFlags;
 
 // On WWW, __EXPERIMENTAL__ is used for a new modern build.