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The time has come: On Dancing With the Stars Season 17 Week 6, the stars will have to double the fun with a second dance. Now's when we'll really get to see who has the goods to make it to the end.

So, what will the main dances be, what's this "Switch-Up Challenge" you've been hearing about, and what else can you expect from the ballroom tonight? We've gathered all of the biggest intel about Week 6 right here.

Lacey Schwimmer returns! Those of you who miss pro Lacey Schwimmer's outgoing personality and eye-catching choreography will be happy to know she's back in the ballroom this week. She choreographed the opening number along with her brother, Benji Schwimmer.

Time for a big musical number. Since DWTS no longer has an extra hour to fill on Tuesdays, there haven't been many big-name stars dropping by to sing songs and promote albums. That changes this week. Fewer dancers means more time to fill, which means it's time for an awesome musical guest. Rising pop princess Ariana Grande will join forces with Mika to perform their duet, "Popular."

The "Switch-Up Challenge." So, what is the switch-up challenge? According to ABC, it's a "fresh take on a dance marathon." Basically, "couples will compete side by side, in two rounds, with no prior knowledge of dance style or musical accompaniment. One by one, the judges will select couples to be tapped-off/removed from the dance floor. Extra judges' points will be awarded to couples based on longevity."

So, basically, the dance marathon with more rules and no prior knowledge of the style. Should be interesting.

Who's dancing what? Despite the extra challenge, this week there's only one main dance. Here's what each celeb will take on:

Amber Riley and Derek Hough: Samba

Bill Engvall and Emma Slater: Tango

Brant Daugherty and Peta Murgatroyd: Tango

Corbin Bleu and Karina Smirnoff: Viennese Waltz

Elizabeth Berkley and Val Chmerkovskiy: Cha-Cha-Cha.

Jack Osbourne and Cheryl Burke: Paso Doble

Leah Remini and Tony Dovolani: Quickstep

Nicole "Snooki" Polizzi and Sasha Farber: Foxtrot

Are you excited for the new challenge? Sound off in the comments below.

Catch the next episode of Dancing With the Stars Season 17 on Monday, October 21, 2013 at 8 p.m. ET on ABC.

Rebecca Martin is an Associate Editor at Wetpaint Entertainment and our resident Game of Thrones, Breaking Bad, and genre TV expert. Follow her on Twitter and Google+!