Jay Z was assaulted by Beyonce's sister Solange inside an elevator at the Met Gala Ball 2014 - and the attack was captured on surveillance video, obtained by TMZ.
According to the site's sources, the fight took place at the Standard Hotel in New York City last week.
Jay Z, Beyonce and Solange can be seen stepping into the elevator, before Solange loses her temper, screaming at Jay before unleashing a violent attack.
A large man, presumably the bodyguard, can then be seen hitting the emergency stop button (presumably to keep the argument private) as he attempts to hold Solange back as she hits and kicks out at her brother-in-law.
Watch the shocking video for yourself:
We wonder what made Solange lash out like that?
All three left the elevator together but, while Beyonce and Solange left the Met Gala in the same car together, Jay-Z was escorted by security to another one - suggesting that Beyonce had sided with her sister in this particular argument.
So far, neither Beyonce, Jay-Z or Solange's reps have commented on the video.