Jessie J has said she’s ‘so sad’ after a man was left fighting for life after a bottle attack at a celebrity-packed party.

The Brit-winning singer had been performing at London’s Pulse underground nightclub at a party thrown by smartphone company BlackBerry, where the incident happened just after midnight on Tuesday.

The star tweeted today (Wednesday) of her concern for the 37-year-old victim, who is described as being in a critical condition.

Jessie said: “My thoughts are with the person who was seriously injured last night at the BlackBerry BBM party. So sad.”

The singer, who had performed hits such as Price Tag, Nobody’s Perfect and Who’s Laughing Now, continued: “I really hope they are OK.”

A 25-year-old suspect was being questioned by police on suspicion of slashing the victim’s neck at the event.

A Scotland Yard spokesman said: “It appears he was injured with a bottle. The man – aged 37 – suffered a neck injury. He was taken by ambulance to an east London hospital where his condition is understood to be critical. One man has been arrested and remains in custody at a south London police station.”

BlackBerry said in a statement: “A serious incident occurred at our BlackBerry event… Our first concern is the well-being of the injured guest. We are doing all we can to assist police with their inquiries and are unable to provide further comment at this time.”