Solange Knowles attacks Jay Z in fight caught on video

Jay Z and his sister-in-law, Solange Knowles, got into an altercation at a Met Gala after-party last week that was apparently caught on surveillance cameras.

TMZ, which obtained and published the video, reports the incident happened at the Standard Hotel in New York. The footage purportedly shows the two stepping into an elevator before Knowles lunges at the rapper and begins hitting and kicking him.

A bodyguard is seen holding her back as Beyonce apparently stands by without getting involved. It's not clear what triggered the fight.

During the middle of the incident, TMZ notes, the bodyguard can be seen pushing the emergency stop button on the elevator, presumably to keep the fight private.

All three attended the annual Costume Institute Gala last Monday night at the Metropolitan Museum of Art. This past weekend, Jay Z and Beyonce were spotted sitting courtside at a Brooklyn Nets game at the Barclays Center in Brooklyn, N.Y., while Solange Knowles performed at the Vulture Festival at New York's Webster Hall.