Kristi Yamaguchi and Mark Ballas by Kelsey McNeal/ABC
Kristi Yamaguchi and Mark Ballas had just performed their down-and-dirty mambo, gotten another set of near-perfect scores and headed backstage. As Monday's show closed in on a commercial break, Season 5 spitfire Sabrina Bryan bounded out of her chair and crossed to another section of the audience, where Season 4's John Ratzenberger was sitting. They high-fived.

"They nailed it!" says Bryan, proud of her former ballroom partner and real-life boyfriend, Ballas. "I'm so excited."

That was just one slice of the great celebrity-watching the audience was treated to on Monday night. Ratzenberger, an alum of Cheers, sat in one section; a star of Happy Days, Henry Winkler, sat in another. Ratzenberger says he was impressed with Yamaguchi, Jason Taylor and Shannon Elizabeth. Winkler was there to cheer on an old family friend, Marlee Matlin, as was Flashdancer Jennifer Beals, who shares the cast roster with Matlin on Showtime's The L Word.

"It's all very friendly," says judge Carrie Ann Inaba, who has a knack for picking up on the backstage vibes. "But I want to see what it's like Week 3 (next week), because that's the first week after two of them are sent home. Usually, it's then that all this happy stuff goes away. I think it's going to get very serious."

Guess what? It's already serious. Word is that all the stars - and some of the pros - hit a major emotional and physical wall last Wednesday, the day after the two-night premiere. "Oh my god," says Marlee Matlin through her interpreter. "Even Fabian [Sanchez, her pro partner] was feeling it, but not as much as me. I had to sit down on the floor. I had to sip water. I had to go to the bathroom. I was in a total fog." Sanchez agrees. "It was a sluggish rehearsal," he says with wry understatement.

"I was like, 'Oh my god, I'm this crazy person crying on reality television,'" says Marissa Jaret Winokur, whose morning-after fatigue resulted in the crying jag that played out on tape before she danced. "I watch all the reality shows and I think, 'Those people are crazy,' And now I'm one of them." Winokur says it really hit her that she would only have one week to improve on, well, everything. "You're back in rehearsal and it's 8 am and you're like, 'I just want to do better. I want to do more.'" Is she the newest member of Overachievers Anonymous? "I know," she says. "But I can't be because I'm not a ballroom dancer. So I have to let it go."

"I can't move my knees!" yells Penn Jillette, who is overcoming bad knees and feet to perform - and staying in remarkably good humor. "The time that you're out there, actually performing, is fun," he says. "But the rest of it? Teller [his magician partner] and I always say that we've never been paid to do a show. We get paid to rehearse, to show up and to change our clothes. We'd do the show for free." So he doesn't like the glitz and glitter of the ballroom? "I hate makeup, I always have," he says. "And I hate changing my clothes. I'm from New England. I find it embarrassing when they put my makeup on or comb my hair. I don't like being touched."

"I could hardly walk up the stairs last weekend," says Priscilla Presley, who, at age 62, continues to astonish the audience with her remarkable stamina and flexibility. She's also dancing in 4-inch heels, higher than any other celebrity woman. Her pro partner, Louis van Amstel, is on cloud nine. "She can do it," he raves, "and the more she does, the more I want. Sometimes, in this partnership, I am really the student. She's taught me what it means to be yourself. She's a rebel. And I'm a rebel, and I've been pushing it away. But because of her, I'm saying yes, I am going to throw you on the floor, and yes, I am going to have you do that death spiral. I know you're Priscilla Presley, and I know this could be disastrous. But every week, she inspires me more and more."

Pro Jonathan Roberts was all about encouraging his star, tennis great Monica Seles, who had a rough first night and came out this night with a lighter attitude. "You know what? I'm kind of getting it a little better now," she says. "The judges should have rewarded her improvement," says Roberts. "This week, she improved, she smiled more, there was shaking, there were hips!"

Ask Roberts if his former partner, Heather Mills, is going to share her new wealth (from her divorce from Paul McCartney) with her Dancing friends, and he says, "Heather has been so wonderful to me. Whenever Anna and I go to England, she lets us stay at her apartment there. She comes and meets us for dinner. I still talk to her every week."

Tell Yamaguchi that it looks like all she had to do was toss her ice skates in the corner and show up to impress the judges, and she begs to differ. "No, no, no," she says. "This is eight hours a day of hard work. And tonight, I covered up because I almost tripped in these heels. I was like, 'Look up here, don't look down there!'" In fact, Yamaguchi's greatest achievement may be mastery over her nerves. "Backstage," she says, "I was silent before we went out and my stomach was in a knot. I knew that our dance was probably going to shock people." But didn't she ever do anything raunchy on skates in the exhibition dancing that follows every major competition? "I had some fun numbers, yes, but it seems so long ago. Here, I have to be worried about getting the steps, and working with a partner, and getting the right hand-hold."

Says Ballas, "We have very similar personalities. Very laid-back but very focused and determined. When we're in the studio, we don't sit around and chat. We work."

Like we said, it's already serious. - Deborah Starr Seibel