Cameron Diaz showed off her engagement ring and laughed with a pal as she broke the news of her engagement to Benji Madden, on Tuesday.

The actress had just shared the news with her friend, as she left Barney's, having done some last-minute Christmas shopping at the sale (where half of LA was on Tuesday and Wednesday, BTW).

Diaz, 42, had been dating the Good Charlotte rocker, 35, for only seven months before he popped the question. She's already met his parents and already discussed NOT wanting children. But perhaps marriage will make her feel differently?