diff --git a/clmm/theory/ccl.py b/clmm/theory/ccl.py
index 2bcdb4500..281728e0f 100644
--- a/clmm/theory/ccl.py
+++ b/clmm/theory/ccl.py
@@ -108,9 +108,8 @@ def _update_halo_density_profile(self):
         """updates halo density profile with set internal properties"""
         # prepare mdef object
         if self.massdef == "virial":
-            self.mdef = ccl.halos.MassDef("vir", self.mdef_dict[self.massdef])
-        else:
-            self.mdef = ccl.halos.MassDef(self.delta_mdef, self.mdef_dict[self.massdef])
+            self.__delta_mdef = "vir"
+        self.mdef = ccl.halos.MassDef(self.delta_mdef, self.mdef_dict[self.massdef])
         # setting concentration (also updates hdpm)
         self.cdelta = self.cdelta if self.hdpm else 4.0  # ccl always needs an input concentration
 
diff --git a/tests/test_theory_parent.py b/tests/test_theory_parent.py
index 09bc8fa3a..dd26bbf2d 100644
--- a/tests/test_theory_parent.py
+++ b/tests/test_theory_parent.py
@@ -94,13 +94,13 @@ def test_instantiate(modeling_data):
 
     if theo.be_nick in ["nc", "ccl"]:
         mod.set_halo_density_profile(massdef="virial")
-        assert_equal(mod.massdef, "virial")
+        assert_equal(mod.delta_mdef, "vir")
 
         # reset
         mod.massdef = "mean"
 
         mod.massdef = "virial"
-        assert_equal(mod.massdef, "virial")
+        assert_equal(mod.delta_mdef, "vir")
 
     if theo.be_nick == "nc":
         import gi