Billy Joel

Olivia Rodrigo delights fans at Billy Joel’s latest MSG performance.

Rodrigo then joined Joel to sing “Deja Vu” and “Uptown Girl” for some of the audience members who were old enough to be her grandparents. However, there were surprisingly more people in the audience who knew the words to “Deja Vu” than you might expect. Meanwhile, Joel nodded and smiled from his piano bench.

As bittersweet as “Deja Vu” is as a breakup song, it was all love between Rodrigo and Joel, who made a surprise appearance during the latest of the New York legend’s monthly residency at MSG.

“I love her music — and so do my kids,” Joel said as he introduced the three-time Grammy winner from his revolving piano. After letting Rodrigo have all of the attention on “Deja Vu,” Joel got up from his piano and joined her for a fizzy “Uptown Girl” duet. It demonstrated how much the music of the 73-year-old transcends generations.

Joel has welcomed a slew of surprise guests, from Bruce Springsteen and Jon Bon Jovi to Tony Bennett and Miley Cyrus, since beginning his Garden residency in January 2014. And this one has to be one of the most surprising of them all.

But it was also ironic that Joel was embracing — and being embraced by — one of the hottest young artists during Harry Styles’ 15-show run at the Garden, which began last Saturday. It was almost as if he was telling New York that he wasn’t going to be the irrelevant old man in his own home.

“I’d like to thank Harry Styles for taking the night off so we could kind of cram in here,” he joked.

Joel then thanked the audience for patiently waiting two years for this COVID make-up show, which had been postponed from 2020.

“I’m not sure I’d do that for myself,” he admitted. “In any case, it’s great to be back at the Garden.” We’re now the house band.”