British pop star Jessie J has apologised to fans after bowing out of an upcoming music festival in Switzerland. The Price Tag hitmaker was due to play the Heitere Open Air event in Zofingen, alongside acts including Rita Ora, Empire of the Sun, Pitbull and Public Enemy. But now the 25-year-old singer has dropped out of the event with less than a week to go before her scheduled slot on 9 August (13). Taking to her Twitter.com page on Saturday (03Aug13), Jessie J tweets, "Heartbeats (fans), sorry I have to pull out of Fridays Zoffingen (sic) festival due to recording/promo commitments in the USA. So gutted not see you!"