JT will be taking to the stage towards the end of the September festival, on Sunday 29, with Jessie J performing on Monday 23 September.
Once again, entry to the festival is absolutely free - tickets can be won online by entering into a ballot.
The festival will be held at The Roundhouse in Camden, London, and for the more tech-savvy among us (and any not lucky enough to get tickets!) it will also be streamed live via iTunes and Apple devices.
Jessie J, who's just debuted her new single Wild, told Capital Radio that she's planning another style shake-up for the music gig.
"I'm excited to see you all at this year's iTunes Festival," she said. "I'll be back with new music, a new look and a party you're all invited to!"
Other artists announced so far include Queens of the Stone Age, Phoenix, Jake Bugg, Jack Johnson, 30 Seconds to Mars and Primal Scream. We're looking forward to seeing Justin Timberlake in his Suit and Tie - but with another 22 acts still to be announced, we can't wait to see who else will be joining him!
Visit the iTunes website to enter for tickets now.
WATCH: JUSTIN TIMBERLAKE - INSTYLE CRUSH