Jessie J has offered her condolences to the man who was seriously injured at last night's (April 3) BlackBerry party in London.

The event, which was to promote BlackBerry mobile phones, took place at Pulse nightclub in Southwark and also featured a performance from Wretch 32, but was marred by violence as a party-goer was stabbed in the neck.

The victim, according to police, is in a serious condition and the 'Price Tag' sensation took to social networking site Twitter earlier this afternoon to pass on her well-wishes:

"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."

The songstress also announced that she will play her first ever gig in Los Angeles to a crowd of 500 people at The Roxy on April 9.

Watch Jessie J perform 'Who's Laughing Now' from the showcase below: