Taylor Swift dresses as Olaf, performs with Idina Menzel at Halloween concert

Taylor Swift saved her most chilling celebrity duet of the year for Halloween.

Dressed as Olaf the snowman from Disney's "Frozen," the pop star brought actress Idina Menzel onstage at her Tampa, Fla. concert to sing the animated blockbuster's trademark song, "Let It Go."

 

Swift surprised concertgoers when she disappeared backstage, only to quickly reemerge in her Olaf costume. Her background dancers, meanwhile, donned reindeer outfits as the singer addressed the crowd.

"I don't know if you noticed but we have a 'Frozen' theme going on here," Swift said to the audience. "If only Idina Menzel were here."

Menzel then appeared through a trap door in the stage, dressed as her royal character in "Frozen," Elsa.

The audience roared and sang along as the two stars performed the iconic hit, leaving Swift buzzing even after the concert ended.

 

"Frozen totally happened tonight," Swift wrote on Instagram. "And 55,000 people sang 'Let it Go' so loudly, it nearly took my breath away. Good times, @idinamenzel."

Menzel, who won a Grammy for her rendering of "Let It Go" in 2014, was also excited afterwards, calling the performance an "out of body experience."

"Or out of Elsa's body experience!" she jokingly clarified on Instagram.

"Let It Go" became an instant success after "Frozen" hit theaters in late 2013, selling nearly 11 million copies in 2014 to make it fifth-highest selling song of the year.

The catchy track earned a Grammy, an Academy Award and a Radio Disney Music Award, and it was also nominated for a Golden Globe.

 

Menzel was the latest high-profile star to join Swift onstage during her critically acclaimed "1989" Tour, as singers Selena Gomez, Justin Timberlake, The Weeknd and Mick Jagger have all performed alongside her in the past few months.

Other prominent figures such as Los Angeles Lakers guard Kobe Bryant, comedian Chris Rock and talk show host Ellen DeGeneres have also appeared at recent shows.

The Halloween concert marked the final show in America for Swift on her long-running tour. She will perform in Singapore, China and Australia, with the final performance taking place in Melbourne on Dec. 12.