diff --git a/param/parameterized.py b/param/parameterized.py
index 597f0a21f..d97126970 100644
--- a/param/parameterized.py
+++ b/param/parameterized.py
@@ -5341,6 +5341,9 @@ def __init__(self,overridden,dict_,allow_extra_keywords=False):
         #  def __init__(self,overridden,**kw):
         #      ...
         #      dict.__init__(self,**kw)
+        for pname, pobj in overridden.param.objects().items():
+            if pname in dict_:
+                pobj._validate(dict_[pname])
         self._overridden = overridden
         dict.__init__(self,dict_)