Last year, when the huge-on-arrival teenage pop star Olivia Rodrigo released her second single “Deja Vu,” Rodrigo’s lyrics included a kind of unexpected shoutout. In an accusatory address to an ex who’s already moved on, Rodrigo say, “I bet that she knows Billy Joel because you played her ‘Uptown Girl.'” That moment was fun for conflicting reasons. On the one hand, doesn’t everyone know Billy Joel and “Uptown Girl”? On the other, why would present-day teenagers be thinking about Billy Joel at all? But also, why wouldn’t they? “Uptown Girl” could be grandparent music for someone Rodrigo’s age, but sometimes, grandparent music still hits.

Earlier this year, Olivia Rodrigo headed out on her first tour. She covered a lot of the alt-rock hits of the ’90s and ’00s, and she shared the stage with surprise guests like Alanis Morissette, Avril Lavigne, and Natalie Imbruglia. Last night, an older legend invited Rodrigo onto his stage. It was Billy Joel, who seems happy for the “Deja Vu” mention. He should be. I bet a lot of people know Billy Joel because Olivia Rodrigo mentioned “Uptown Girl.”

Billy Joel no longer releases music, but he still sells out Madison Square Garden, his hometown arena, anytime he feels like it. Last night, Joel once again headlined the Garden, and during his show, he brought Olivia Rodrigo to the stage. Joel introduced Rodrigo by reeling off the various awards that she’s won and then continued: “She’s got all kinds of awards. She’s very talented. I like her music, and so do my kids.”

Rodrigo seemed very excited to be there, and she proceeded to sing “Deja Vu” with Joel and his band, dramatically pointing at Billy Joel during the lyrics that mentions him. (I’m not entirely clear whether Joel was doing anything during that song. He might’ve been playing piano?) Joel’s fans know “Deja Vu” well enough for a full-arena singalong. Then, Rodrigo and Joel sang “Uptown Girl” together, and it was adorable. Watch a fan-made video below.

When Billy Joel released River Of Dreams, his last pop album, Olivia Rodrigo was a full decade away from being born. Rodrigo wasn’t even born when Joel came back for his classical LP Fantasies & Delusions in 2001. She still clearly loves his music, and I think that’s awesome.