diff --git a/NAMESPACE b/NAMESPACE
index f1481b6dd..b2cd13aa2 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -183,4 +183,4 @@ S3method(unique, IDate)
 S3method(unique, ITime)
 S3method('[<-', IDate)
 S3method(edit, data.table)
-
+S3method(as.IDate, IDate)