Photo of Kendrick Lamar by Kathy Kmonicek/AP

Kendrick Lamar surprised fans Saturday night when showed up on stage during The Weeknd's Vevo Presents show in Los Angeles.

The pair performed "Sidewalks," from The Weeknd's newest album Starboy, which arrived last month.

As seen in the fan footage below, many in the audience at first seemed to think Lamar's verse was simply from pre-recorded audio—that is, until he visibly took the stage.

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