diff --git a/piker/ui/_label.py b/piker/ui/_label.py
index 8bda1839..1a22951e 100644
--- a/piker/ui/_label.py
+++ b/piker/ui/_label.py
@@ -274,7 +274,7 @@ class FormatLabel(QLabel):
 
     def format(
         self,
-        fields: dict[str, Any],
+        **fields: dict[str, Any],
 
     ) -> str:
         out = self.fmt_str.format(**fields)