diff --git a/include/Client_Session.h b/include/Client_Session.h
index caf73c673..1e6cdd401 100644
--- a/include/Client_Session.h
+++ b/include/Client_Session.h
@@ -13,7 +13,7 @@
 
 #ifndef PROXYJSON
 #define PROXYJSON
-namespace nlohmann { class json; }
+#include "../deps/json/json_fwd.hpp"
 #endif // PROXYJSON
 
 class MySQL_Session;