Dunno if he counts as "famous" but... for a BREAKING NEWS scandal, how about Justin Sane, lead singer of Anti-Flag, a well-established (since 1988) punk band. For 35 years Sane's stage persona was of a militantly progressive singer, especially on women's issues. One of their songs is “Feminism Is for Everybody”, and Sane was a VERY vocal supporter of the #MeToo movement.
Except *Rolling Stone* just published [a long story](https://www.rollingstone.com/music/music-features/anti-flag-justin-sane-1234817170/) in which 13 women accuse him of violent sexual assault. Many were in high school at the time. One was 12.
When the rest of the band heard the news they immediately broke up and released a statement saying something like "this isn't the guy we thought we knew for 35 years". I'm not sure I believe that. The *Rolling Stone* piece mentions a couple times when the band *had* to know. For instance, Sane once (allegedly) took a girl to a shed behind a venue, and the rest of the band were (supposedly) making "where's Justin?" jokes, as if they knew.