As many of us know, ex-boyfriends, girlfriends and partners are strictly off-limits to friends – but in the quirky corners of Hollywood, these rules don't always apply.
While we have a 'whole world' to explore when it comes to new relationships, celebrities are typically confined to a small circle of A-listers and socialites.
Watch MM Confessions: My Partner Doesn't Know... Post continues after video.
So, it's no surprise that there are quite a few celebs who are good pals and happen to share a former partner or two.
Here are the 10 celebrities who are seemingly totally okay with other celebs dating their exes.
Sienna Miller and Tom Sturridge... who may be dating Alexa Chung.