Tristan McManus and Pamela Anderson Tristan McManus and Pamela Anderson

If you're still shocked that Dancing with the Stars All-Stars boasts six former champs, you're not the only one.

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"To be honest, I didn't think we'd get that many," executive producer Conrad Green tells "It's quite incredible, isn't it? I was hoping we'd get a good response and it was more than any of us could've expected. This whole cast is really the cream of the cream of the crop."

That's not an overstatement: Of the 13 returning stars, only two of them — Pamela Anderson and Sabrina Bryan, who's back via fan vote — didn't make the finals in their original seasons. Two third-place finishers (Bristol Palin and Melissa Rycroft) and three runners-up (Kirstie Alley, Joey Fatone, Gilles Marini) also join the ex-Mirrorball winners (Helio Castroneves, Shawn Johnson, Drew Lachey, Kelly Monaco, Apolo Anton Ohno and Emmitt Smith).

"I think it's a testament to how much they enjoyed it the first time that so many winners and finalists are back," Green says. "Looking at it on paper, you can argue one or two people who you wanted to see back who aren't there, but almost everybody we approached said yes. The problem is this show requires you for three months and a lot of other people had committed to other things already. This has always been a really fun interlude in their careers, so I think a lot of them, if they were able to, made the space for it. And now we have a really crazy, competitive cast."

Having such a formidable bunch means that there will be some tweaks to the show. Celebrities will be creative directors of a dance for a week, for which they'll come up with the theme and wardrobe, pick the music and all but choreograph their routine. Gone is the Dance Duel, which was introduced last season to prevent a Sabrina Bryan-like shocking elimination (though Green allows that it may return in a normal season) and in is a temporary scoring system emphasizing technique. "We're thinking about having Len [Goodman] give a couple of extra points to the celebrity who did the best technical dance of the night," Green says. "It's an extra boost; it's not a punishment for everyone else. We'll tweak scoring here and there to make sure there's a bit more discipline and content in there, given that these people have done the show before."

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But the biggest change of all, of course, was born out of necessity: Assembling eight new pairs, a result of multiple celebs having had the same pro in their respective seasons or pros who are no longer on the show. "We talked to the celebrities themselves and found out how much it mattered to them to be with their original partners and we kept that in mind. Obviously, if there was no overlap, you'll get the same partner. But also, we wanted to make exciting new couples," Green says. "It is inherently a bit odd for them to see their partners with someone else, but I think everyone understands you can't replicate people."So how did Green & Co. come up with the new couples? Find out below.

Pamela Anderson and Tristan MacManus
The Baywatch babe cha-cha-ed on Season 10 with Damian Whitewood, in his sole season on the show, and exited in a somewhat surprising sixth place. "I think Tristan's warmth and the fact that he's so popular will really help Pam. Maybe she'll do better this time," Green says. "She's really funny — dry funny. He gets that kind of humor. She's gonna have her work cut out since outside of Sabrina, she's the only person who never made the finals. I think they both have a lot to prove. The problem is she's traveling in this training period. If she can get past the first show, she can be up and running."

Helio Castroneves and Chelsie Hightower
Size matters. At 5-foot-8, Castroneves is one of the shorter male celebs (Drew Lachey is two inches shorter) and seemed to be the perfect fit for the petite Hightower, who is blonde and sunny like the Indy 500 champ's former partner Julianne Hough. "You have to look at height and what everyone would look like as a pairing," Green says. "Helio is one of the loveliest guys we've ever had on the show. He's got that incredible smile and energy, and Chelsie's similar. They're getting along really well. She's got a slightly more contemporary style of dancing [than Hough], she's got a lot of different influences in her dancing, so I think she'll challenge Helio."

Shawn Johnson and Derek Hough
Hough is a three-time champ, but, ironically, he has no returning partner, so he gets his BFF Mark Ballas' former pupil. "What's interesting for Shawn was when she came on, she was a kid. She was 17 years old. She was very mature in terms of competition and stuff, but she was very young," Green says. "I think the challenge for Derek, in a way, is how do you make people relook at Shawn? In her season, she was, not a surprise winner, but it was such a competitive season that I don't think a lot of people called her to win it until right at the very end when Mark did that brilliant freestyle with her. She wants to prove that she's got the poise to do it, and obviously Derek's a fantastic choreographer. I think they should be very good."

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Drew Lachey and Anna Trebunskaya
The 98 Degrees crooner has been a constant presence on Dancing since winning in Season 2 with Cheryl Burke — over Trebunskaya and Jerry Rice. "I love the hangover of 'You're the one who beat me!' between them," Green says. "He's so funny. Anna's very funny and feisty. They're already bickering at each other in the fun-loving way." Green pegs the pair as a dark horse, what with Lachey's "great competitive spirit" and his affable personality. "As much as anyone ever has on the show, he really gets the humor and the warmth of the show and how to be on the show. It's not just about dancing; it's about engaging and having fun with it. Drew's got so much of that charm and the dance ability that I think they're gonna be a really good package."

Gilles Marini and Peta Murgatroyd
Let's just call a spade a spade. "That's gonna be hot," Green sums up. "I think that's gotta be the lowest body fat couple we've ever had on the show. Gilles is tall, so he needed someone tall, and they look marvelous together." Looks aside, Marini has the skills to back it up and his loss to Johnson three years earlier still stings with fans. "Perhaps with Gilles and more than anybody else in the cast, he's the one people say, 'You should've won,'" Green continues. "That's no denigrating Shawn at all because she's perfectly justified as a winner, but the competition that season was so tough and a lot of people called him all the way through as the winner, so he's got this pressure of 'Now I need to come strong again and win it.' That should be interesting."

Kelly Monaco and Val Chmerkovskiy
How different was Season 1 from the current incarnation of Dancing? "It wasn't even high-def when Kelly did it!" Green cracks. The inaugural champ will have her work cut out for her since Season 1 was a mere six weeks — and so will Chmerkovskiy, who has yet to make it past Week 3. "They're getting on real well and I think they're both very determined to make it far, especially Kelly," Green says. "She's gonna have to work that hard to keep up with the level of competition. That's part of the challenge she's embraced. But no matter what happens on this season, you always have your place in the Dancing pantheon."

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Apolo Anton Ohno and Karina Smirnoff
No female pro does tough love better than Smirnoff, and Ohno will be ready to take it and then some. "They are both workhorses, so I think they'll push each other," Green says. "They also have this positivity and light about them. I can't wait for fans to see it. They're really ones to watch." Even more so now that Ohno, who hasn't competed in short track since the 2010 Vancouver Olympics, can fully devote himself to Dancing. "Last time, he was doing training for short track on top of what he was doing here and I remember for the first show, he only did like a week's worth of training with Julianne because he was preparing for the world championships, which he won," Green says. "So you've got to think, without that 'distraction,' how much better is he going to be? I'd be terrified!"

Sabrina Bryan and Louis van Amstel
Bryan, unsurprisingly, beat out Kyle Massey and Carson Kressley for the viewers' choice slot and probably has the most pressure to deliver. "Not only did she go through the whole process of campaigning to be on the show, but everyone's still talking about her early elimination all these years later. She wants to come and right her wrong," Green says. "Obviously, she couldn't be with Mark again since he's already with Bristol. Style-wise, she and Louis will be phenomenal together. Louis' choreography is high and fast and pointed and very tricky, and Sabrina's got that ability to nail it."

Between the eight new couples and the five original re-pairings, Green believes fans will get "the best of both worlds." "You'll have your favorite couples back and get some new ones, so that's extra spin and excitement," he says. "I honestly can't be happier with how it turned out."

Dancing with the Stars premieres Monday at 8/7c on ABC.