He's already proved himself a triple threat on-screen in Disney's "High School Musical" series, and the 24-year-old will now get to prove his ballroom merit with Karina Smirnoff.
Despite an ongoing battle with terminal cancer that her doctor only recently revealed to be "pretty close to a remission," Harper will be part of the season 17 cast. The 74-year-old will be joined by returning pro dancer Tristan MacManus.
Actor, television host and all-round "Science Guy" Nye, 57, will groove with "Dancing" first-timer Tyne Stecklein.
The 25-year-old reality TV star will follow in the footsteps of her former fellow "Jersey Shore" cast member, Mike "The Situation" Sorrentino," by taking the "Dancing" stage. She'll work with former Troupe member and first-time pro Sasha Farber.
The "Pretty Little Liars" star, 28, will waltz with Peta Murgatroyd.
The 27-year-old actress and singer, best known for her role as Mercedes Jones on "Glee," will learn from "Dancing's" only four-time champ, Derek Hough.
The 31-year-old actress, singer-songwriter and social media correspondent for "The Voice" will dance with two-time pro winner Mark Ballas.
Actor-comedian Engvall, 56, will move to the music with newbie pro Emma Slater.
The 41-year-old film and television star behind memorable parts in "Saved By the Bell" and the now-cult classic "Showgirls" will hit the floor with Val Chmerkovskiy.
The retired NFL wide receiver, 41, will learn the ballroom basics from Sharna Burgess.
The 27-year-old reality TV star, who was diagnosed with multiple sclerosis in 2012, plans to show fans his dance-floor skills alongside two-time champ Cheryl Burke.
The former "King of Queens" actress, 43, who made headlines when she left the Church of Scientology earlier this year, will learn the steps with hoofer Tony Dovolani.