diff --git a/trytond/trytond/model/fields/one2one.py b/trytond/trytond/model/fields/one2one.py
index 0a44fba384..ccef8ae9dd 100644
--- a/trytond/trytond/model/fields/one2one.py
+++ b/trytond/trytond/model/fields/one2one.py
@@ -54,7 +54,7 @@ class One2One(Many2Many):
     def __set__(self, inst, value):
         Target = self.get_target()
         if isinstance(value, dict):
-            value = Target(*value)
+            value = Target(**value)
         elif isinstance(value, int):
             value = Target(value)
         assert isinstance(value, (Target, type(None)))