Chicago high schoolers at Chance the Rapper's "Open Mike" event were blessed tonight with a surprise performance from Kanye West and Vic Mensa. The Chi-Town MCs hit the stage to perform "All Day" and "U Mad," and the kids in attendance went appropriately nuts.

Watch more clips from the performance below.

"All Day"

Omg !! pic.twitter.com/E5XP6mBQq3 — No Regular Party (@ElzTheDJ) May 12, 2015

"U Mad"

Kanye West and Vic Mensa just went on at Open Mike in Chicago oh my fucking god pic.twitter.com/Z8vuSMRBRk — James Tylers (@TylerHotel) May 12, 2015

Kanye and @VicMensa performing "U Mad" during Chance The Rapper's Open Mike in Chicago today pic.twitter.com/zooPuxhsmv — Team Kanye Daily (@TeamKanyeDaily) May 12, 2015