Hollywood was shocked earlier this year when funnyman Jim Carrey and funny lady Jenny McCarthy announced they were breaking up--and for the first time since the split, McCarthy is sharing some insight into what happened.

The Playboy model-turned-actress-turned-author discusses the relationship on an episode of 'The Oprah Winfrey Show' that airs Tuesday,PEOPLE reports.

McCarthy visits Oprah's couch to discuss her latest book, 'Love, Lust and Faking It,' and while there, is asked what happened with Carrey. "Tell me, when did you know it was over?" Winfrey asks.

McCarthy candidly answers, "You know, the simple word I can give – and there's a few, so let me say a few. The first thing is, when it's not fun anymore, you need to start investigating and do an inquiry into the relationship."