The American Idol judge told talk show host Ellen DeGeneres she felt so scared that the British comedian would embarrass her and husband Marc Anthony that she confronted him backstage.
'I was sitting in the audience and was thinking 'Oh my God, what's he gonna say about me? Maybe he'll just joke about Alec (Baldwin)' and then I went back stage and I got him,' she told the audience, during Tuesday's appearance on the afternoon show.
'Right before I was about to go out, I was standing back there and he came over.
'I can't say everything I said - because you'd have to bleep it out and nobody needs to know that I talk like that - but I said 'Listen, I'm from the Bronx, I fight, my husband fights, and I'll beat you up after the show!'