Looks like someone in The O.C. can keep a secret!

Vicki Gunvalson's mom only found out her famous daughter had cosmetic surgery by watching the Real Housewives of Orange County this past Monday, even though the two had seen each other right after she had the procedure several months ago.

Gunvalson -- who was once called “Miss Piggy” by Slade Smiley during a standup routine -- defended her right to go under the knife while talking to reporters at the Bravo upfronts in New York City Wednesday night.