Kendrick Lamar surprised fans of The Weeknd when he popped on stage during the Canadian singer's special Vevo show in L.A. on Saturday (Dec. 17).

The Weeknd was running through tracks from his newest successful release, Starboy and Kendrick joined him for a live performance of one of the album's standouts, "Sidewalks," backed by a live band. The Weeknd labeled K.Dot a "genius" after their collaboration on the song.

“He’s a genius,” he told Beats 1. “He probably came in the afternoon and left late at night. He did it there on the spot. He played the record over and over. I played him songs, the ‘Starboy’ theme, of course, which he incorporated into his verse. He would just walk around, we had food, and he’s writing his verse in his head. He’d go to his phone, look at it a few, put it back in, start walking around. He then at one point went into the studio booth, closed the door, and I could hear him yelling his verse.”

The Weeknd has had a lot of success with Starboy thus far. A few weeks ago, he broke Spotify's record for most streams in a day, with over 36 million streams. The album also debuted at No. 1 on the Billboard 200 chart as well.

Check fan footage of the performance below.

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