Taylor Swift hasn't been up to much since that infamous phonecall recording appeared on Kim Kardashian’s Snapchat last month. But on Saturday the songstress emerged from hiding to join rapper Nelly onstage for a special performance of his 2002 hit ‘Dilemma’.

Swift was in the Hamptons celebrating her friend Karlie Kloss’ 24th birthday when the rapper invited her on stage to take Kelly Rowland’s part in the duet. Dressed in a black crop top and mini skirt combo, Swift appeared in good spirits as she sang and danced with Nelly.

More: Scott Eastwood: "No One Wanted Me To Do Taylor Swift Video"

Speaking to E! News a fellow guest at the event confirmed that Swift’s boyfriend Tom Hiddleston was not present, but she was still having fun. "Taylor was in an amazing mood, and super fun all night. She danced her ass off,” the insider said.

“At first she didn't want to perform but then Nelly asked her. Everyone was super into it, the crowd loved it.” It’s not the first time Nelly and Swift have performed together. Last year he joined her onstage in St. Louis, Missouri during her 1989 tour to perform a special rendition of ‘Hot in Here’ with girl-group Haim.

More: "Taylor Swift What Up?" - Justin Bieber Sides With Kanye

While the big party was on Saturday, model Kloss actually turned 24 last Wednesday and Swift posted a special message on Instagram to celebrate her friend’s big day. "I LOVE YOU KARLIE," Swift captioned a selfie of the pair. "You're such an exquisite person, always trying to make things better for others. Every day I'm inspired by how giving, loving, and thoughtful you are. Happy 24th Birthday!!! @karliekloss."

A photo posted by Taylor Swift (@taylorswift) on