diff --git a/eolian_cxx/colourable.eo b/eolian_cxx/colourable.eo
index 9a28aac2..a34f74c8 100644
--- a/eolian_cxx/colourable.eo
+++ b/eolian_cxx/colourable.eo
@@ -59,6 +59,6 @@ class Colourable (Eo.Base)
         }
     }
     events {
-        colour_changed(int);
+        colour_changed: int;
     }
 }