A music fan is fighting for life in hospital after being stabbed at a party where Jessie J sang.
The pop star was performing at a party held by phone giants BlackBerry in London.
It was attended by a galaxy of celebs.
The man, in his 30s, was stabbed in the neck with a bottle at midnight.
The victim was rushed to hospital and a man was detained by cops.
A reveller said, “It happened in the main area to the right of the stage where the bar is after Jessie J had performed.”
A police spokesman said, “The man was injured with a bottle. We are still investigating the case.”
Later, Jessie J offered her sympathy to the victim of the assault,
She sent a message via Twitter, “My thoughts are with the person who was seriously injured last night at the BlackBerry BBM party. So sad. I really hope they are ok.”