Solange Knowles “viciously attacked” Jay-Z in a lift after the Met Gala, reports say.

The younger sister of Beyoncé lashed out at her brother-in-law after they all attended a Gala after-party at New York City’s The Standard Hotel. In footage from the lift obtained by TMZ, the 27-year-old can be seen squaring up to the 99 Problems singer before starting to scream and lash out at him.

“A large man -who appears to be a bodyguard --attempts to hold Solange back, but she manages to connect at least 3 times,” the outlet reports.

The singer then manages to lash out with her legs and aims her kicks at Jay-Z’s crotch but he manages to grab her foot at one point and avoid it making contact.

Her 32-year-old sister was also in the lift at the same time and appeared to plead with her sibling to calm down. But Beyoncé at no point gets physically involved or consoles either her husband or her sister. The website also points out that the bodyguard is seen hitting the emergency stop button on the 12th floor in the middle of the fight, no doubt trying to keep the fracas private.

“It's unclear what triggered the fight,” TMZ added, as Solange and the 44-year-old had previously been known to have a very close relationship.

The trio were all photographed leaving the hotel together after the incident, Solange walking ahead with a face like thunder while Beyoncé followed with her husband. However she then joined her sibling in a car while Jay-Z got into another vehicle by himself.

Solange is still following her brother-in-law on Twitter and neither star’s rep has so far commented on the footage.