Surprise! Rihanna joins Paul McCartney on the Desert Trip stage

At the first weekend of the Desert Trip music festival in Indio, Calif., attendees saw Paul McCartney perform with Neil Young. This second weekend? They saw that, and were raised one better.

Surprise! Rihanna also joined McCartney for their hit FourFiveSeconds. 

YouTube user Monte Lawson shared a clip of Rihanna's welcome appearance at "Oldchella." (And no, FourFiveSeconds co-songwriter Kanye West did not show up.)

Once the song ended, the two hugged and Rihanna left the stage. "Ladies and gentlemen, Rihanna, the one and only," McCartney said.