Mockito: When a mock Object's void method is called, use a real Object's void method instead

I want to do this:

when(GridLayout.class).addComponent(Matchers.any(Component.class), Matchers.anyInt(), Matchers.anyInt()).thenUseInstead(realLayout.addComponent(...));

Where GridLayout is my mock object and realLayout is a real Layout object.

I spotted doAnswer in the MockitoAPI (I think thats what I want?) however I am struggling to put it all together.

MockitoAPI 'doAnswer' example:

  doAnswer(new Answer() {
      public Object answer(InvocationOnMock invocation) {
          Object[] args = invocation.getArguments();
          Mock mock = invocation.getMock();
          return null;
      }})
  .when(mock).someMethod();

Can anyone help?