Solange Knowles reportedly attacked Jay Z after she ''overreacted'' to something he said.

The 27-year-old singer ''flipped out'' at the rapper, 44, in an elevator at the Met Gala after-party in New York last week because she was offended by a comment he made.

More: Solange Knowles beats Beyonce's husband Jay-Z in elevator

A source told Us Magazine: ''Solange flipped out over something Jay had said, that she took the wrong way. She took it too hard or too far. Not sure what it was, but she greatly overreacted.''

Solange was caught on surveillance kicking and clawing her brother-in-law as they left the bash held in the Boom Boom Room at The Standard Hotel in New York City, last Monday (05.05.14).

Jay didn't appear to retaliate as the brunette beauty screamed in his face, but he did attempt to hold her hands down as their bodyguard struggled to hold her back.

Beyoncé appeared to stay calm and collected throughout the scuffle and watched on helplessly as her sister violently attacked her husband.

However, at one point, the 'XO' hitmaker - who has two-year-old daughter Blue Ivy with Jay - intervened and said something to Solange after she began punching him again.

Solange then stormed out of the elevator with a disgruntled expression plastered across her face as Beyoncé, 32, and Jay followed shortly behind.

The siblings were then seen getting into a car together, while the 'Holy Grail' hitmaker opted to travel alone.