Jay Z, Solange Knowles

Solange Knowles allegedly attacked her brother-in-law Jay-Z in an elevator last week, according to surveillance video obtained by TMZ.

In the video, Beyonce's sister can be seen physically attacking Jay-Z in a Standard Hotel elevator while the group was on their way to a Met Gala after party last Monday. A man who appears to be a bodyguard attempted to hold Solange back, but she continued to throw kicks, while Beyonce looked on from the corner. It's unclear what the argument was about.