Jay Z and Beyoncé were all smiles on the red carpet at the Met Gala last week (with the mock proposal, and all) but things may have gotten very ugly by the end of the night.

On Monday (May 12), TMZ released new footage that appears to show Jay Z being violently attacked by a woman alleged to be his sister-in-law, Solange Knowles, in an elevator. (MTV News could not independently verify the clip at press time.)

The video footage shows Jay Z, Solange and Beyoncé all stepping into an elevator at what the gossip site said was the Standard Hotel in New York City. Within seconds, the woman alleged to be Solange completely loses it. She begins to kick and punch Hov, while the rapper -- dressed in a tux -- tries to fend off her blows.

A bodyguard steps in between to break things up, but even he can't prevent the woman from landing a last kick. There's no audio in the footage, so it's impossible to know what Beyonce said during the altercation, but she definitely is not seen getting in between the two in the footage released by TMZ.

A second video shows a trio that appears to be Jay, Bey and Solange all leaving the party moments later. As Jay appears to attempt to enter the same car as his wife and sister-in-law, but a security guard stops him and direct him to another car instead.

MTV News will keep you updated as more details emerge.