Cher

Cher surprised movie fans at CinemaCon in Las Vegas on Wednesday by performing a cover of ABBA's hit "Fernando."

Actress Amanda Seyfried took to the stage at The Colosseum in Caesars Palace to preview an extended clip of her movie musical Mamma Mia! Here We Go Again, a follow-up to 2008's Mamma Mia!, during the Universal studio presentation at CinemaCon.

In the clip, Cher, as her character Ruby Sheridan, leads an elaborate performance sequence to ABBA's hit "Super Trouper," and following the footage, Amanda stunned the audience by revealing that they had a surprise up their sleeve - Cher live on stage.

The veteran singer, who wore a full glitter pantsuit and matching platform heels, appeared on a raised platform from behind fake palm fronds to the audience's delight, and proceeded to sing "Fernando" surrounded by dancers performing a choreographed routine.

Later that day, the Believe star wrote on Twitter, "Just got back from Vegas , Did Fernando on stage at Coliseum (sic),For Cinemacon Convention.They created look of the island & set in MAMMA MIA 2. Ppl seemed to like song."

The musical marks Cher's first film role since 2010's Burlesque. She is also best known for her performances in Mermaids, The Witches of Eastwick, and Moonstruck, for which she won the Best Actress Oscar.

Cher and Lily James are new additions to the musical's cast, which also features returning stars such as Meryl Streep, Pierce Brosnan, Christine Baranski and Colin Firth. The film will go back and forth in time to show how relationships forged in the past resonate in the present, and will use ABBA songs not featured in the first film, as well as some fan favorites.