The festival will run over the whole month of September at the city's Roundhouse venue, with two artists performing each night.
'Trampoline' hitmaker, Tinie said: ''I'm excited to be back at the iTunes Festival with a whole bunch of new music. It's going to be crazy!''
Bastille - who played at the iTunes Festival in 2012- also can't wait to take to the stage again next month.
Leader Dan Smith said: ''We can't wait... Last year we were massively distracted by seeing ourselves on giant TV screens for the first time! Hopefully, this year the crowd will also know some of our songs.''
Avicii, who is currently sitting at the top of the UK singles chart with 'Wake Me Up' said: ''I'm feeling super excited to be playing the iTunes Festival - really looking forward to being back in London after the great show at the Electric Daisy Carnival a couple of weeks ago.''
The festival will kicks off on September 1st and free tickets can be applied for by visiting iTunesfestival.com
Current line-up for the iTunes festival 2013:
Sept 02 - Sigur Rós + Poliça
Sept 03 - The Lumineers + Phox
Sept 04 - Paramore + Fenech-Soler
Sept 05 - Rizzle Kicks
Sept 06 - Queens of The Stone Age + Palma Violets
Sept 07 - Phoenix + Little Green Cars
Sept 08 - Bastille + 1975
Sept 09 - Arctic Monkeys + Drenge
Sept 10 - Jake Bugg + Valerie June
Sept 11 - Kings of Leon + Jimmy Eat World
Sept 12 - Elton John + Tom Odell
Sept 13 - Avicii
Sept 14 - Chic featuring Nile Rodgers + Janelle Monáe
Sept 15 - Vampire Weekend + The Olms
Sept 16 - Jack Johnson + Bahamas
Sept 17 - Ludovico Einaudi
Sept 18 - Thirty Seconds to Mars + The Family Rain
Sept 20 - Primal Scream
Sept 23 - Jessie J + Lawson
Sept 25 - Pixies + NO CEREMONY///
Sept 26 - Tinie Tempah
Sept 28 - John Legend + Robin Thicke
Sept 29 - Justin Timberlake
The BBC drama starring Aidan Turner returns to BBC One on September 4th.