On Aug. 24, the "We Didn't Start the Fire" singer, 73, brought out Olivia, 19, as a surprise guest during his show at New York City's Madison Square Garden after she referenced him in her 2021 single "Deja Vu."
"I'm going to bring up another young musician. This is a very talented singer-songwriter," he said before naming some of the awards the Sour singer has won. "I like her music and so do my kids. Please say hello to Olivia Rodrigo."
As Olivia took the stage, she thanked the legendary singer for having her, adding, "I'm such a huge fan and I couldn't have written the next one without you, so thank you."
The two then performed Olivia's single "Deja Vu," in which she sings, "I'll bet that she knows Billy Joel / ‘Cause you played her ‘Uptown Girl.'"
But they didn't just sing Olivia's hit. Following their first performance, Billy hugged Olivia and announced to the audience that they would perform "Uptown Girl," or as he said, "the song that was referred to in the last song."
Following the epic performance, the "drivers license" singer shared pictures of herself with Billy backstage on her Instagram Stories, captioning the post, "biggest honor ever still crying thank u Billy!!!!!!"
In another post, Olivia shared a video she took of the crowd at Madison Square Garden singing along to Billy's classic hit "Piano Man."
She captioned the clip, "I SANG WITH BILLY JOEL AT MADISON SQUARE GARDEN TODAY ARE U KIDDING."