diff --git a/lib/hkStubs/CMakeLists.txt b/lib/hkStubs/CMakeLists.txt
index d60f9d99..20207f3b 100644
--- a/lib/hkStubs/CMakeLists.txt
+++ b/lib/hkStubs/CMakeLists.txt
@@ -104,6 +104,7 @@ add_library(hkStubs OBJECT
   Havok/Physics2012/Collide/Shape/Query/hkpShapeRayCastInput.h
   Havok/Physics2012/Collide/Util/Welding/hkpWeldingUtility.h
 
+  Havok/Physics2012/Dynamics/Action/hkpAction.h
   Havok/Physics2012/Dynamics/Collide/hkpResponseModifier.h
   Havok/Physics2012/Dynamics/Common/hkpMaterial.h
   Havok/Physics2012/Dynamics/Common/hkpProperty.h
diff --git a/lib/hkStubs/Havok/Physics2012/Dynamics/Action/hkpAction.h b/lib/hkStubs/Havok/Physics2012/Dynamics/Action/hkpAction.h
new file mode 100644
index 00000000..c0411c9c
--- /dev/null
+++ b/lib/hkStubs/Havok/Physics2012/Dynamics/Action/hkpAction.h
@@ -0,0 +1,89 @@
+#pragma once
+
+#include <Havok/Common/Base/hkBase.h>
+
+class hkStepInfo;
+class hkpEntity;
+class hkpSimulationIsland;
+class hkpPhantom;
+class hkpWorld;
+
+class hkpAction : public hkReferencedObject {
+public:
+    HK_DECLARE_CLASS_ALLOCATOR(hkpAction)
+    HK_DECLARE_REFLECTION()
+
+    inline explicit hkpAction(hkUlong userData);
+    explicit hkpAction(hkFinishLoadedObjectFlag flag) : hkReferencedObject(flag), m_name(flag) {}
+
+    ~hkpAction() override = default;
+
+    virtual void applyAction(const hkStepInfo& stepInfo) = 0;
+    virtual void getEntities(hkArray<hkpEntity*>& entitiesOut) = 0;
+    virtual void getPhantoms(hkArray<hkpPhantom*>& phantomsOut) {}
+
+    inline hkpWorld* getWorld();
+
+    virtual void entityRemovedCallback(hkpEntity* entity) = 0;
+
+    inline hkUlong getUserData() const;
+    inline void setUserData(hkUlong data);
+
+    inline const char* getName() const;
+    inline void setName(const char* name);
+
+    virtual hkpAction* clone(const hkArray<hkpEntity*>& newEntities,
+                             const hkArray<hkpPhantom*>& newPhantoms) const = 0;
+
+    // For internal use.
+    inline hkpSimulationIsland* getSimulationIsland();
+    inline void setSimulationIsland(hkpSimulationIsland* island);
+    inline void setWorld(hkpWorld* owner);
+
+private:
+    hkpWorld* m_world;
+    hkpSimulationIsland* m_island;
+
+protected:
+    friend class hkpWorld;
+    friend class hkpWorldOperationUtil;
+    friend class hkpSimulationIsland;
+
+    hkUlong m_userData;
+    hkStringPtr m_name;
+};
+
+inline hkpAction::hkpAction(hkUlong userData)
+    : m_world(nullptr), m_island(nullptr), m_userData(userData) {}
+
+inline hkpWorld* hkpAction::getWorld() {
+    return m_world;
+}
+
+inline hkUlong hkpAction::getUserData() const {
+    return m_userData;
+}
+
+inline void hkpAction::setUserData(hkUlong data) {
+    m_userData = data;
+}
+
+inline const char* hkpAction::getName() const {
+    return m_name;
+}
+
+inline void hkpAction::setName(const char* name) {
+    m_name = name;
+}
+
+inline hkpSimulationIsland* hkpAction::getSimulationIsland() {
+    return m_island;
+}
+
+inline void hkpAction::setSimulationIsland(hkpSimulationIsland* isl) {
+    m_island = isl;
+}
+
+inline void hkpAction::setWorld(hkpWorld* owner) {
+    m_world = owner;
+}