diff --git a/bindings/pyroot_experimental/PyROOT/src/CppCallablePyz.cxx b/bindings/pyroot_experimental/PyROOT/src/CppCallablePyz.cxx
index 00fe6cdea4d8a5be182b90e0501556d529ce1f62..fcab8efaafcfc7d6873851b01befa48c99b901ca 100644
--- a/bindings/pyroot_experimental/PyROOT/src/CppCallablePyz.cxx
+++ b/bindings/pyroot_experimental/PyROOT/src/CppCallablePyz.cxx
@@ -690,7 +690,7 @@ PyObject* ProxyCallableImpl_call(PyObject * /*self*/, PyObject *args)
 // Method definition for class used as decorator to create C++ wrapper
 static PyMethodDef CallableImplMethods[] =
 {
-    {"__init__", (PyCFunction)GenericCallableImpl_init, METH_VARARGS|METH_KEYWORDS, "Parse decorator arguments"},
+    {"__init__", (PyCFunction)(void(*)(void))(GenericCallableImpl_init), METH_VARARGS|METH_KEYWORDS, "Parse decorator arguments"},
     {"__call__", ProxyCallableImpl_call, METH_VARARGS, "Create C++ wrapper function"},
     {NULL, NULL, 0, NULL}
 };