Penelope Cruz keeps mum on engagement questions!

Miss Cruz appeared on David Letterman last night and was asked point blank if she was engaged to Javier Bardem. Despite the fancy rock on her finger, she refused to answer stating, "I don't feel comfortable talking about my private life in public. I've been here a few times with you, you know I'm tough. One thing I don't do, I don't lie about my personal life," she said. "It's sacred to me. It's my life. But I don't give details about it because I am allergic to that." The couple have been seen at various events being quite intimate with one another.