Rap mogul Jay Z and his sister-in-law Solange Knowles reportedly became embroiled in an explosive altercation in a Standard Hotel elevator following last week's (05May14) Met Gala in New York - and surveillance video footage of the drama has now appeared online.

It is not known why angry Solange lashed out at her sister Beyonce's husband but the footage, obtained by Tmz.com appears to show the singer punching and kicking the 99 Problems hitmaker as a bodyguard attempts to drag her away from the rapper.

At one point in the grainy black and white video, Beyonce steps between her sister and her husband and appears to attempt to calm her sibling down.

Halfway through the minute-long video, the minder presses the the emergency stop button, presumably to keep the fight private.

Solange has personal and professional relationship with Jay Z - she is also signed to his management company Roc Nation.