diff --git a/elfspy/Fake.h b/elfspy/Fake.h
index 25765eb..fca5c61 100644
--- a/elfspy/Fake.h
+++ b/elfspy/Fake.h
@@ -16,7 +16,7 @@ namespace spy
  * The constructor installs the new function in place of the function, the
  * destructor uninstalls it
  */
-
+class Fake;
 template <typename H, typename ReturnType, typename... ArgTypes>
 extern std::vector<std::shared_ptr<Fake>> fake_list;
 void delete_mocks (void) {