You never know where a member of the A$AP Mob will pop up these days. Earlier in the week, we heard Rocky on Sam Smith's "I'm Not the Only One (remix)," and now we're treated to A$AP Ferg's collaboration with SBTRKT.

"Voices in My Head," with its dark, moody beat, gives Ferg the spotlight and a chance to show off his flexibility. Bet you didn't expect the guy who brought us "Shabba" and "Work" to end up on a song like this. The eerie background vocals and drums on this one are courtesy of Warpaint.

The song will be the last thing you hear on SBTRKT's upcoming album, Wonder Where We Land.

"I started this in London with an idea I recorded on an upright piano," SBTRKT explained when he premiered the track. "Took this to Los Angeles (set up at Fleas the Boat studio in Silver Lake) collaborating further with Stella (drums) & Emily (vocals) from Warpaint - took this back to london to work more arrangement ideas to it and finally a couple months later took that to New York (Downtown - The Roots were in the studio next door!) and collaborated with Ferg ([shout] to our friend Callender for connecting us)."