Apple today announced that it will once again hold its monthlong iTunes Festival in London this year, with 30 nights of concerts at The Roundhouse during the month of September. The full schedule of performances is yet to be announced, but Apple has revealed that the lineup will include Justin Timberlake, Thirty Seconds to Mars, Jack Johnson and Jessie J.“This year’s iTunes Festival is the best ever with an incredible lineup of global superstars and stellar emerging artists,” said Eddy Cue, Apple’s senior vice president of Internet Software and Services. “Music fans around the world are going to love watching this incredible month of music, whether in London at the Roundhouse or on their iOS device. We’re honored so many renowned artists are part of this year’s lineup.”