Taylor Swift Wins Halloween with 'Frozen' Costume and On-Stage Duet

Taylor Swift invited Frozen singer Idina Menzel on stage during her final U.S. concert in Tampa Bay, Florida, on Saturday night.

In the spirit of Halloween, the 25-year-old star dressed up as the film's character, Olaf, and belted out a live version of Let it Go alongside Menzel, who was dressed as Elsa.

Taylor Swift dresses up as Olaf alongside Idina Menzel, dressed as Elsa, from Frozen. Photo: Getty

Menzel, 44, was the final guest among a long list of celebrities who joined Swift on stage during the American leg of her world tour.

The Out of the Woods singer will now continue her 1989 tour in Singapore, China and Australia.

PHOTOS: Celebs Dress Up for Halloween

PHOTOS: Celebs Dress Up for Halloween