After the annual event - which has previously starred Pamela Anderson and Donald Trump as roastee's - the 63-year-old told reporters her performance was "terrific". You could've set it at any other time of the year (especially as it was, weirdly, released in July) and it'd still work just as well.
Deadline.com said Moore was a surprise guest who teased her ex-partner about his age, baldness, music, movie career and relationship skills in front of a crowd that included Willis' current wife, model Emma Heming.
Bruce Willis has finally weighed in on a long conversation about "Die Hard".
The "G.I. Jane" star, who was married to Willis from 1987 to 2000, joked, per People: "I was married to Bruce for the first three "Die Hard" movies, which makes sense, because the last two sucked".
Finally: "People wondered why our marriage came to an end".
The stars came out on Saturday night to the Comedy Central Roast of Die Hard institution and American treasure Bruce Willis - and it was a celebratory festival of reading the non-Oscar nominated actor to filth.
Bruce is the latest victim to be skewered by Comedy Central and Demi did not disappoint.
Not to be outdone, Willis had some choice words for MC Gordon-Levitt - and Moore.
"This is a real personal moment for me, to be here roasting my dead cousin's second-favorite action star", said comic Nikki Glaser.
Whether or not his statement was for comedic effect, it's clear the actor's opinion couldn't be any clearer, as he considers Die Hard another of one of his famed action movies as opposed to holiday viewing.
A report from IndieWire suggests he went even further by doubling down with "It's a g*****n Bruce Willis movie!"
"It was very surprising and very cool", he said, appearing relatively shocked.