Two comedians male have a good run a secret of homosexuality is revealed at the end. I can not remember much more. The actors I am sure are fairly popular. I think it was made in early 2000. There is a reporter in the movie telling the story of these two men. It was close to the rat pack era.

Where the Truth Lies (2005)
Starring Kevin Bacon, Colin Firth, Alison Lohman

You can read the plot summary here:
Where the Truth Lies - Wikipedia, the free encyclopedia

Summary excerpt:
Karen discovers that Maureen had secretly recorded her interactions with Morris and Collins. Gradually, it becomes clear what really happened that night 15 years before: the three had engaged in a ménage à trois, fueled by drugs and booze, and at some point Collins tried to have sex with Morris, who resisted violently. When Collins retreated to his room, Maureen tried to blackmail Morris to keep this information secret; in 1957, it would have finished Collins professionally and personally if it had come out that he was bisexual. Collins passed out in his room, Morris in his, and Maureen fell asleep on the couch. In the morning, she was dead.