UPDATE: Rick Ross' DJ, Sam Sneaker, as well as an MTV News source confirmed that the fight actually happened, although apparent Cassie was not the cause. According to Sam Sneaker's Twitter:
Drake is having one hell of a bad weekend if all these rumors are to be believed. It's apparently not enough that Chris Brown accused Karrueche Tran of cheating on him with Drake (even if Tran denied it and Brown later apologized). Oh, no. Now it appears that the rapper might have gotten in a fight with another rap legend on Sunday. According to Twitter, P. Diddy punched Drake in the face at Club LIV, and, no, it's not because Drake stole Diddy's mic back in February.
Since the rumor is making its rounds on social media without video evidence or a word from either rapper to back it up, details are sparse. Currently, the popular story is that Drake was attempting to flirt with Diddy's girl, Cassie Ventura, while drunk all night and, after several attempts to get him to stop, Diddy just punched him — and possibly dislocated Drake's shoulder at the same time. Whether the story is true or not, the Internet seems quite content to run with it, make jokes about it, and speculate on how the fight actually went down, especially since this rumor crops up so soon after the Brown-Tran-Drake love triangle. In fact, Drake has picked up a new nickname from his fans: Mr. Steal Yo Girl.
If you're looking for any kind of video of the event, you're out of luck so far. About the only kind of proof we have is rapper Ace Hood posting a video of himself laughing on Instagram along with the caption, "Club Liv aftermath lol!" From that, we can at least assume that something went down at LIV and that that something definitely involved Drake and Diddy — though whether it was a fist fight and whether that fist fight was really over Cassie still remains to be seen. At this point, I would call this one a hilarious rumor and let it go. It just seems a little too convenient for Drake to be involved in two alleged cheating scandals in the same weekend.