Can't wait until Track 13 is revealed as a Roar remix so we can put these Rihanna collab rumours to rest for another 3 years. I've been boycotting Rihanna since the Birthday Cake remix was released, I would not appreciate Katy forcing me to listen to her.
and about those 'Dark Horse not on iTunes' rumours a couple pages back, I definitely think it will be on iTunes, but I have a feeling it might force you to pre-order the entire album before you get the song. Would be pretty logical for Capitol to do that, no point in letting Dark Horse take away from Roar's sales.