diff --git a/dlls/physcallback.h b/dlls/physcallback.h
index 1db276e0..305102aa 100644
--- a/dlls/physcallback.h
+++ b/dlls/physcallback.h
@@ -19,6 +19,7 @@
 #include "physint.h"
 
 // Must be provided by user of this code
+extern BOOL gPhysicsInterfaceInitialized;
 extern server_physics_api_t g_physfuncs;
 
 // The actual physic callbacks
diff --git a/dlls/world.cpp b/dlls/world.cpp
index 4ac56925..089db6b5 100644
--- a/dlls/world.cpp
+++ b/dlls/world.cpp
@@ -822,6 +822,8 @@ static physics_interface_t gPhysicsInterface =
 	DispatchPhysicsEntity,
 };
 
+BOOL gPhysicsInterfaceInitialized = FALSE;
+
 int Server_GetPhysicsInterface( int iVersion, server_physics_api_t *pfuncsFromEngine, physics_interface_t *pFunctionTable )
 {
 	if( !pFunctionTable || !pfuncsFromEngine || iVersion != SV_PHYSICS_INTERFACE_VERSION )
@@ -835,5 +837,6 @@ int Server_GetPhysicsInterface( int iVersion, server_physics_api_t *pfuncsFromEn
 	// fill engine callbacks
 	memcpy( pFunctionTable, &gPhysicsInterface, sizeof(physics_interface_t) );
 
+	gPhysicsInterfaceInitialized = TRUE;
 	return TRUE;
 }