Kanye West surprised the crowd at Kid Cudi's concert Saturday night with his first appearance on stage in a year.
Kanye and Cudi performed "Father Stretch my Hands, Pt. 1" at Chicago's Aragon Ballroom. Cudi's in the middle of his Passion, Pain & Demon Slayin' World Tour.
Kanye hasn't been on stage since cancelling his Saint Pablo Tour last November. You'll recall he had a mental breakdown and ended up at the UCLA psychiatric ward, but he has bounced back in a big way.
TMZ broke the story ... Kanye's been working on a new album..