diff --git a/siwe/siwe.py b/siwe/siwe.py
index 4dc047c..a2b5ac7 100644
--- a/siwe/siwe.py
+++ b/siwe/siwe.py
@@ -138,7 +138,7 @@ def from_datetime(
     ) -> "ISO8601Datetime":
         """Create an ISO-8601 formatted string from a datetime object."""
         # NOTE: Only a useful classmethod for creating these objects
-        return (
+        return ISO8601Datetime(
             dt.astimezone(tz=timezone.utc)
             .isoformat(timespec=timespec)
             .replace("+00:00", "Z")