Katy Perry has announced she is "pumped" to be closing the iTunes festival.
The Roar singer will close the month-long free music festival at the Roundhouse in London.
Katy tweeted: "PUMPED to announce I will be closing the month-long @iTunesFestival on 9/30 with my friends @IGGYAZALEA & @iconapop opening!"
Lady Gaga will open the festival on September 1 and other headline acts include Robin Thicke, Sir Elton John, Justin Timberlake, John Legend, Kendrick Lamar and the Kings Of Leon.
Roar is Katy's best-selling single on iTunes with more than 544,000 copies sold domestically alone, according to Apple.
The annual festival will be streamed on the iTunes festival app and available for download.