Why did Rihanna have a meltdown at the Grammys?

Rihanna singing at a Grammys event only two days before she mysteriously pulled out of her big performance. / Getty

Rihanna was “screaming and hysterical” before pulling out of her Grammy performance blaming bronchitis, according to reports.

The pop star was screaming and hysterical before she bailed on the Grammys, TMZ reports, but as to what triggered the outburst, that’s not clear.

The singer was loudly expressing displeasure over her rehearsal, and sources say she was loud and upset and bailed on the event, the gossip website reported.

A rep for Rihanna said she had a medical issue, namely bronchitis, which was apparently so bad that she could not perform and that’s why she left.

But TMZ say sources close to RiRi allege she was too upset to stay and watch the show.

Interestingly, Rihanna sang flawlessly two nights before the Grammys at a Lionel Richie charity event.

Several sources say her voice was also great at the Grammys rehearsal.