The singer will headline the event at London's Roundhouse venue in Camden on September 21.
© PA Images
"I was gutted to not have played at last year's iTunes Festival, so this year is going to be epic," Jessie J told Metro.
"The Roundhouse is one of my favourite London venues. I can't wait!"
Jessie J pulled out of last year's event after breaking her leg and was replaced on the bill by Hard-Fi.
Tickets for the show are free for competition winners, and can be applied for on the festival website.
Other artists confirmed for this year's month-long series of gigs include One Direction, Noel Gallagher's High Flying Birds and Labrinth.
Watch Jessie J's music video for 'Who You Are' below:
