Demi Moore is Surprise Guest for Bruce Willis Roast

Bruce Willis grinned and beared it during Saturday night's roast, but he was unprepared for the surprise guest of the evening -- his ex-wife Demi Moore.

Bruce is the latest victim to be skewered by Comedy Central and Demi did not disappoint. One of her best lines ... "I look at our marriage like "The Sixth Sense" ... You were dead the whole time."

Bruce and Demi were married from 1987 - 2000. They had 3 kids -- Rumer, Tallulah and Scout, and all of them were cackling in the audience.

Cybill Shepard, who co-starred with Bruce in his breakout role -- "Moonlighting" -- also took her shots.