One of the most highly anticipated moments of Taylor Swift’s concerts during The Eras Tour is the “surprise song” acoustic segment. It comes late in the show, between segments devoted to “The Tortured Poets Department” and “Midnights,” the final chapter.

Swift often brings along special guests to help her sing the surprise songs, which are never known in advance and always delight fans.

After singing alone Friday night, Swift planned the ultimate shock in New Orleans on Saturday when he called on pop superstar Sabrina Carpenter to join her on stage.

Carpenter encouraged Swift to sing her hit “Espresso” on the guitar, which she mixed with “Is It Over Now?”

“Can I do it?” Swift asked Carpenter.

“You can do it,” Carpenter replied, wearing a short white babydoll dress.

“Oh my God, I’m about to do it,” Swift said, before uttering the infamous Carpenter line: “I work late because I’m a singer.”

But the fun didn’t stop there.

The two then sang together a mash-up of “Please, Please, Please” and “Espresso” as fans shouted the lyrics from their seats.

Swift added that Carpenter couldn’t make the first night of the tour because she only had Saturday off.

Surprise songs on Friday evening

On Friday, the first of Swift’s three sold-out nights at New Orleans’ Caesars Superdome, she took to her debut album for “Our Song,” which she paired with “Call It What You Want” from “Reputation,” in the acoustic guitar mash-up up.

A piano mash-up of ‘The Black Dog’ from ‘Tortured Poets Department’ and ‘Haunted’ from 2010’s ‘Speak Now’ followed.

The previous weekend in Miami, Florence Welch of Florence + the Machine made a surprise appearance with Swift to perform “Florida!!!” to sing; Welch also appeared on the recorded version of the song.

Nola.com reporters Chelsea Shannon and Lauren Walck contributed to this report.