diff --git a/interop/src/cpp/types/koala-types.h b/interop/src/cpp/types/koala-types.h
index 9ab5ac39bca1cd1885904b99185f59c3b13f4c4b..ccc191cb529aa6189900c3171e16847832123b78 100644
--- a/interop/src/cpp/types/koala-types.h
+++ b/interop/src/cpp/types/koala-types.h
@@ -111,6 +111,10 @@ struct KInteropNumber {
       this->tag = INTEROP_TAG_FLOAT32;
       this->f32 = value;
     }
+    KInteropNumber(InteropNumber value) {
+      this->tag = value.tag;
+      this->i32 = value.i32;
+    }
     InteropNumber toCType() {
       InteropNumber result;
       result.tag = this->tag;