diff --git a/features/lwipstack/LWIPStack.h b/features/lwipstack/LWIPStack.h
index 4c13ab3946..c35c3c239d 100644
--- a/features/lwipstack/LWIPStack.h
+++ b/features/lwipstack/LWIPStack.h
@@ -450,7 +450,7 @@ private:
      *  @param func     Callback to be called
      *  @return         0 on success, negative error code on failure
      */
-    nsapi_error_t call_in(int delay, mbed::Callback<void()> func);
+    virtual nsapi_error_t call_in(int delay, mbed::Callback<void()> func);
 
     struct mbed_lwip_socket {
         bool in_use;