'Dancing' alum Ginger Zee goes behind the scenes at dress rehearsals before week 4

— -- "Good Morning America's" Ginger Zee went behind the scenes of Sunday's "Dancing With the Stars" dress rehearsal to check in with the contestants and compare notes from her time on the competition about the effort and excitement that builds before each performance.

"I love this part of the competition because you finally see something different in their eyes," Zee said on "GMA." "I think it’s when the biggest growth starts, because they all start to break a little bit and reality sets in, and then you really start to get vulnerability and emotion."

After an impressive first two weeks for Nick Viall and his professional partner, Peta Murgatroyd, the pair told Zee that their one-on-one time has paid off as they prepare to take the stage first this week. But Viall said that he is focused on getting past the emotions so he can perfect his moves.

"It's funny, I tell you. I actually get more nervous on Sundays for camera blocking, because you spend all week rehearsing in a studio, and then you come here, and the stage is all set up the way you planned it out," the former Bachelor told Zee. "But you're seeing it live for the first time and the lights and the camera. As you know, you get to do it five or six times before the actual performance, and that helps."

Zee, a "Dancing" alum, also caught up with four-time Olympic gold medalist Simone Biles and her partner, Sasha Farber.

"Dress rehearsal day — is this your least or favorite day?" Zee asked.

"I think it's the most nerve racking out of the whole process leading up to it," said the gymnast. "Sundays are a little bit scary."

After Zee introduced herself, Mr. T politely said he knew all about her.

"I watch you on the show doing the weather and whatnot, and then you did this show," he said. "I watched it and said, 'Wow, how is she going to get back and do the weather now?'"

The wrestler-turned-actor told Zee the audience is getting to see a new side of him, thanks to the show.

"You know, I'm more than just a guy who beats people up, even though I love beating people up sometimes. I don't have any problem with that," he said with a laugh. "This dance shows my range. I can be smooth. I can be warm."

"Many of them are performers, so they play characters. They sing, and they dance," Zee said of the contestants. "They do all of these things, but this is the first time they're playing themselves, and especially in this dance, because it's for their mother, like Mr. T is doing, or it's for their children, like Nancy Kerrigan. It's a really special night."

The remaining pairs will show off their new moves as the competition heats up on the dance floor Monday night on ABC at 8 p.m. ET.