Wow. Looks like Kanye's doing at least some of the recently rumoured Blueprint 3!
Here's a clip of Kanye and Jay-Z doing a new joint that samples what sounds like some UK rapper saying "jocking Jay-Z" (or maybe "jacking"?), over which Jay spits:
"That bloke from Oasis said i couldn't play guitar / somebody shoulda told him I'm a fucking rock star / today is gonna be the day that I'm gonna throw it back to you..."