Taylor Swift served “espresso” and more with Sabrina Carpenter in New Orleans on Saturday night (October 26).

Swift teased that she would do something different for her acoustic set at her final stop on the Eras tour — sing someone else's song. “It got stuck in my head,” she told the audience at the Caesars Superdome of her choice, adding a twist to the surprise song menu.

To the delight of many, she launched into Carpenter's massive summer hit “Espresso” on her guitar. Then she paused and asked her fans a stupid question: “Is it okay if I call you and you can say hello?” – and picked up a cell phone to put Sabrina on the phone.

The pop star couple played a little, with Swift putting Carpenter on speakerphone, putting him on the microphone and asking her how long it would take her to get to the stadium.

As it turns out, they were on stage together about five seconds later and reworked “Espresso” into a three-song mashup with Swift's 1989 Vault track “Is It Over Now?” and another big hit from Carpenter: “Please Please Please”.

The highlight of Swift's Saturday night? I had an excuse to sing the “Espresso” lyric “I work late because I’m a singer” in a sold-out stadium around 11 p.m.

“She literally has a day off. She's on tour. “It's crazy that she came to perform for us,” Swift said at the end of her crowd-favorite duet. Carpenter left the stage, leaving Swift to finish the acoustic portion of the evening alone at the piano, where she played a mashup of midnight Bonus song “Hits Different” and 1989 Opener “Welcome to New York.”

Check out clips of their surprise appearance below.