When her Set the World on Fire tour reached Los Angeles last night, Alicia Keys had a little something special planned. During yesterday’s Staples Center performance, Keys surprised the audience with a Janet Jackson impression, busting out the sample that makes up the chorus of “Poetic Justice.” Things really went wild, though, when Kendrick Lamar made an unexpected appearance onstage to join her on the good kid, m.A.A.d city track.

Luckily for those of us who couldn’t make it to L.A. last night, somebody caught the whole thing on tape. Check that out above. 

[via HipHopNMore]