Actress Brooke Shields was mortified when comics at a recent event made jokes at the expense of late celebrities Heath Ledger, Bernie Mac and Estelle Getty.

The 43-year-old star was acting as a panelist at a 72-hour comedy sketch event in New York at the weekend. According to the New York Daily News, Shields became "freaked out" when the stand-ups began mocking the tragic deaths of the actors to get a laugh from the crowd.

A source tells the newspaper, "Everything was going great until three comics came out each playing a dead star. One was playing Heath Ledger as The Joker and he just kept listing prescription pills he had in his pocket. Another was playing Estelle Getty and the third was Bernie Mac's ghost. She (Shields) was so freaked out her eyes welled up and she actually bit her nails at one point. When someone pretended to dump Estelle Getty's ashes on (30 Rock actor) Jack McBrayer's head, Brooke got up and walked offstage. She watched the rest of the show from behind a curtain backstage with a grimace."

A spokesman for Shields says the actress left to talk to the writers, reports the newspaper.

-Check out Brooke Shields' Filmography

-Click to View Gallery