Gobby, motor-mouthed and blessed with an enormous pair of lungs, Jessica Cornish shot to fame in 2011 with a flawed-but-ballsy debut album called 'Who You Are', full of grinding R&B and vocal acrobatics. She has since grabbed even more attention with some well-placed appearances at the Olympics Closing Ceremony and as a guest judge on BBC talent show 'The Voice'. Currently bald after shaving her hair off for charity in March, Jessie J is a reliably brilliant and energetic live act who can belt like the best of them – and at this iTunes Festival show she'll finally have a new album to play from, too. In support are insipid, squeaky-clean and worryingly popular boy band Lawson. Win tickets on the iTunes Store, via www.itunesfestival.com.