diff --git a/activerecord/lib/active_record/locking/optimistic.rb b/activerecord/lib/active_record/locking/optimistic.rb
index 2336d23a1c..1040327a5d 100644
--- a/activerecord/lib/active_record/locking/optimistic.rb
+++ b/activerecord/lib/active_record/locking/optimistic.rb
@@ -190,6 +190,10 @@ module ActiveRecord
         super.to_i
       end
 
+      def serialize(value)
+        super.to_i
+      end
+
       def init_with(coder)
         __setobj__(coder['subtype'])
       end
diff --git a/activerecord/test/cases/locking_test.rb b/activerecord/test/cases/locking_test.rb
index 6c59d7337a..9fc0041892 100644
--- a/activerecord/test/cases/locking_test.rb
+++ b/activerecord/test/cases/locking_test.rb
@@ -169,6 +169,12 @@ class OptimisticLockingTest < ActiveRecord::TestCase
     assert_equal 1, p1.lock_version
   end
 
+  def test_lock_new_when_explicitly_passing_nil
+    p1 = Person.new(:first_name => 'anika', lock_version: nil)
+    p1.save!
+    assert_equal 0, p1.lock_version
+  end
+
   def test_touch_existing_lock
     p1 = Person.find(1)
     assert_equal 0, p1.lock_version