diff --git a/src/Microsoft.AspNet.Identity/IdentityBuilder.cs b/src/Microsoft.AspNet.Identity/IdentityBuilder.cs
index 259fc42a95..3481b848bd 100644
--- a/src/Microsoft.AspNet.Identity/IdentityBuilder.cs
+++ b/src/Microsoft.AspNet.Identity/IdentityBuilder.cs
@@ -16,12 +16,6 @@ namespace Microsoft.AspNet.Identity
             Services = services;
         }
 
-        public IdentityBuilder<TUser, TRole> AddInstance<T>(T obj)
-        {
-            Services.AddInstance(obj);
-            return this;
-        }
-
         public IdentityBuilder<TUser, TRole> AddUserStore(IUserStore<TUser> store)
         {
             return AddInstance(store);
@@ -64,5 +58,12 @@ namespace Microsoft.AspNet.Identity
             Services.AddScoped<TManager>();
             return this;
         }
+
+        private IdentityBuilder<TUser, TRole> AddInstance<TService>(TService instance)
+            where TService : class
+        {
+            Services.AddInstance(instance);
+            return this;
+        }
     }
 }
\ No newline at end of file