diff --git a/ReactCommon/fabric/animations/LayoutAnimationDriver.h b/ReactCommon/fabric/animations/LayoutAnimationDriver.h
index 2a221577529..3aa04f99163 100644
--- a/ReactCommon/fabric/animations/LayoutAnimationDriver.h
+++ b/ReactCommon/fabric/animations/LayoutAnimationDriver.h
@@ -23,6 +23,9 @@ namespace react {
 
 class LayoutAnimationDriver : public LayoutAnimationKeyFrameManager {
  public:
+  LayoutAnimationDriver(LayoutAnimationStatusDelegate *delegate)
+      : LayoutAnimationKeyFrameManager(delegate) {}
+
   virtual ~LayoutAnimationDriver() {}
 
  protected:
diff --git a/ReactCommon/fabric/animations/LayoutAnimationKeyFrameManager.cpp b/ReactCommon/fabric/animations/LayoutAnimationKeyFrameManager.cpp
index 034d871388b..12478e15569 100644
--- a/ReactCommon/fabric/animations/LayoutAnimationKeyFrameManager.cpp
+++ b/ReactCommon/fabric/animations/LayoutAnimationKeyFrameManager.cpp
@@ -212,6 +212,12 @@ void LayoutAnimationKeyFrameManager::uiManagerDidConfigureNextLayoutAnimation(
   }
 }
 
+void LayoutAnimationKeyFrameManager::setLayoutAnimationStatusDelegate(
+    LayoutAnimationStatusDelegate *delegate) const {
+  std::lock_guard<std::mutex> lock(layoutAnimationStatusDelegateMutex_);
+  layoutAnimationStatusDelegate_ = delegate;
+}
+
 bool LayoutAnimationKeyFrameManager::shouldOverridePullTransaction() const {
   return shouldAnimateFrame();
 }
@@ -341,6 +347,8 @@ LayoutAnimationKeyFrameManager::pullTransaction(
           std::chrono::high_resolution_clock::now().time_since_epoch())
           .count();
 
+  bool inflightAnimationsExistInitially = !inflightAnimations_.empty();
+
   if (!mutations.empty()) {
 #ifdef RN_SHADOW_TREE_INTROSPECTION
     {
@@ -817,6 +825,21 @@ LayoutAnimationKeyFrameManager::pullTransaction(
       mutationsForAnimation.begin(),
       mutationsForAnimation.end());
 
+  // Signal to delegate if all animations are complete, or if we were not
+  // animating anything and now some animation exists.
+  if (inflightAnimationsExistInitially && inflightAnimations_.empty()) {
+    std::lock_guard<std::mutex> lock(layoutAnimationStatusDelegateMutex_);
+    if (layoutAnimationStatusDelegate_ != nullptr) {
+      layoutAnimationStatusDelegate_->onAllAnimationsComplete();
+    }
+  } else if (
+      !inflightAnimationsExistInitially && !inflightAnimations_.empty()) {
+    std::lock_guard<std::mutex> lock(layoutAnimationStatusDelegateMutex_);
+    if (layoutAnimationStatusDelegate_ != nullptr) {
+      layoutAnimationStatusDelegate_->onAnimationStarted();
+    }
+  }
+
   // TODO: fill in telemetry
   return MountingTransaction{
       surfaceId, transactionNumber, std::move(mutations), {}};
diff --git a/ReactCommon/fabric/animations/LayoutAnimationKeyFrameManager.h b/ReactCommon/fabric/animations/LayoutAnimationKeyFrameManager.h
index f286bd27a38..4f2a766113a 100644
--- a/ReactCommon/fabric/animations/LayoutAnimationKeyFrameManager.h
+++ b/ReactCommon/fabric/animations/LayoutAnimationKeyFrameManager.h
@@ -14,6 +14,7 @@
 #include <react/mounting/MountingOverrideDelegate.h>
 #include <react/mounting/MountingTransaction.h>
 #include <react/mounting/ShadowViewMutation.h>
+#include <react/uimanager/LayoutAnimationStatusDelegate.h>
 #include <react/uimanager/UIManagerAnimationDelegate.h>
 
 namespace facebook {
@@ -37,7 +38,7 @@ enum class AnimationProperty {
 };
 enum class AnimationConfigurationType {
   Noop, // for animation placeholders that are not animated, and should be
-        // executed once other animations have completed
+  // executed once other animations have completed
   Create,
   Update,
   Delete
@@ -97,6 +98,12 @@ struct LayoutAnimation {
 class LayoutAnimationKeyFrameManager : public UIManagerAnimationDelegate,
                                        public MountingOverrideDelegate {
  public:
+  LayoutAnimationKeyFrameManager(LayoutAnimationStatusDelegate *delegate)
+      : layoutAnimationStatusDelegate_(delegate) {
+    // This is the ONLY place where we set or access
+    // layoutAnimationStatusDelegate_ without a mutex.
+  }
+
   void uiManagerDidConfigureNextLayoutAnimation(
       RawValue const &config,
       std::shared_ptr<EventTarget const> successCallback,
@@ -118,7 +125,19 @@ class LayoutAnimationKeyFrameManager : public UIManagerAnimationDelegate,
       MountingTelemetry const &telemetry,
       ShadowViewMutationList mutations) const override;
 
+  // LayoutAnimationStatusDelegate - this is for the platform to get
+  // signal when animations start and complete. Setting and resetting this
+  // delegate is protected by a mutex; ALL method calls into this delegate are
+  // also protected by the mutex! The only way to set this without a mutex is
+  // via a constructor.
+ public:
+  void setLayoutAnimationStatusDelegate(
+      LayoutAnimationStatusDelegate *delegate) const;
+
  private:
+  mutable std::mutex layoutAnimationStatusDelegateMutex_;
+  mutable LayoutAnimationStatusDelegate *layoutAnimationStatusDelegate_{};
+
   void adjustDelayedMutationIndicesForMutation(
       SurfaceId surfaceId,
       ShadowViewMutation const &mutation) const;
diff --git a/ReactCommon/fabric/uimanager/LayoutAnimationStatusDelegate.h b/ReactCommon/fabric/uimanager/LayoutAnimationStatusDelegate.h
new file mode 100644
index 00000000000..b87b96f68f7
--- /dev/null
+++ b/ReactCommon/fabric/uimanager/LayoutAnimationStatusDelegate.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+namespace facebook {
+namespace react {
+
+class LayoutAnimationStatusDelegate {
+ public:
+  /**
+   * Called when the LayoutAnimation engine state changes from animation nothing
+   * to animating something. This will only be called when you go from 0 to N>0
+   * active animations, N to N+1 animations will not result in this being
+   * called.
+   */
+  virtual void onAnimationStarted() = 0;
+
+  /**
+   * Called when the LayoutAnimation engine completes all pending animations.
+   */
+  virtual void onAllAnimationsComplete() = 0;
+};
+
+} // namespace react
+} // namespace facebook