Kylie Minogue
We wouldn't call it a brand new dance—but the Australian pop star still had everybody doing "The Locomotion"!
Cast of Newsies
It's a fine life when the cast of a Broadway show comes to town.
Susan Boyle & Donny Osmond
The Scottish singing sensation teamed with Utah's finest for "This Is the Moment."
Katherine Jenkins
The season-14 runner-up performed il duetto with Plácido Domingo of the operatic "Come What May."
Justin Bieber
They can't get enough of the Biebs on this show. He was back in the first week of season 15 to warble "As Long as You Love Me."
Chris Brown
A year after Tom Bergeron let it be known he didn't want to interview that week's musical guest, the controversial Grammy winner made an uneventful—albeit energetic—return.
Sugarland & Matt Nathanson
The trio joined forces for "Run" on the first results show of season 14.
Justin Bieber & Boyz II Men
The teen heartthrob teamed up with the man-band to perform "Fa La La," off his new Christmas album, Under the Mistletoe.
Julianne Hough & Kenny Wormald
The DWTS alum returned as a guest dancer for the first time to bust a move with her Footloose costar.
Blake Shelton
The country artist and Voice judge had the ballroom rockin' to "Footloose."
Kelly Clarkson
We must ask: Is "Mr. Know It All" about Maksim Chmerkovskiy?
The Band Perry
The country newcomers may sing about dying young, but they won't soon be forgotten.
Kristin Chenoweth
The Tony Award winner showed up on both shows during Broadway week.
Demi Lovato
The Unbreakable starlet belts out her hit single "Skyscraper."
Harry Connick Jr.
We wouldn't mind seeing the crooner compete on the show—anyone else?
LMFAO
The duo gets everyone movin' with their "Party Rock Anthem."
Lady Gaga
What show in its right mind doesn't include a special appearance by this superstar? Just dance, indeed!
Christina Aguilera
The Grammy winner lent her Voice to this show first.
Jennifer Lopez
"Let's Get Loud," encouraged the future American Idol judge.
Pia Toscano
She didn't win American Idol, but Pia got a plum performance slot while flame-for-awhile Mark Ballas did a rumba demo.
Chris Brown
His appearance created a bit of controversy when host Tom Bergeron passed beforehand on interviewing the comebacking R&B star, saying he wouldn't be able to not mention Brown's past troubles.
New Kids on the Block & the Backstreet Boys
The back-in-action boy bands strutted their right stuff right here—and season one contestant Joey McIntyre got to show off some of his moves!
Florence + the Machine
DWTS knew to pencil in the British newcomer just as her dog days were ending.
OneRepublic
Guess who had "All the Right Moves"?