Download Castle Walls - T.I. feat. Christina Aguilera
Penned and produced by newcomers, Skylar Grey and Alex Da Kid, who are responsible for a wave of hits including Rihanna & Eminem's "Love The Way You Lie", Diddy & Dirty Money's "I'm Coming Home" and B.o.B & Hayley Williams "Airplanes". The duo's Top 40 sound is pretty remarkable, being described as "Coldplay meets Hip-Hop" and quickly becoming a mainstay on the charts.