Lady Gaga has unveiled brand new rehearsal footage with fans online just one day ahead of her performance at iTunes Festival 2013.Capitalfm The 'Marry The Night' singer has also confirmed the name of another new 'ARTPOP' song as 'Sex Dreams', while revealing footage of herself dancing and performing the song as she prepares fro her concert at the Camden Roundhouse in London this weekend. Gaga shares a number of lyrics to the explicit song on her Twitter account, while sharing the video of her and her backing dancers perfecting the moves to accompany the track, which follows a slower sound to the other 'ARTPOP' songs revealed so far. The US star is set to kick off iTunes Festival on Sunday (1st September) with her first UK show of the year and her first main Concert.