James Van Der Beek Says 'My Pants Have Gotten Looser' Since Starting DWTS

James Van Der Beek has two-stepped his way into being the Dancing with the Stars frontrunner — but he’s not stepping on a scale.

While he’s noticed changes in his body, the Dawson’s Creek star said he doesn’t know how much weight he’s lost since he began his quest for the Mirrorball Trophy on season 28 of the ABC dance competition series.

“I haven’t stepped on a scale, but my pants have gotten looser,” he told PEOPLE backstage at the iHeartRadio Music Festival in Las Vegas on Friday.

Van Der Beek, 42, added that he may have a leg up on the competition in terms of fitness.

“I was training, I was fight-training for something for like six months,” he revealed. “So I was in pretty good shape, but not dancing shape. It’s a whole other level.”

RELATED: Kel Mitchell Thinks James Van Der Beek Is His Biggest Competition on DWTS — ‘He’s in the Zone’

And while the actor took a slight break from training to attend the iHeatRadio event, it came after a four-and-a-half hour session with his DWTS partner Emma Slater.

“I knew it was going to be hard. I was prepared for a really, really steep learning curve,” he said. “It’s about what I expected. I had no illusions going in. I knew it’d be a lot of work. I knew it would be a ton of time. I just really wanted to do it.”

Asked if Slater ever gets frustrated with him in rehearsals, Van Der Beek laughed, “If she has, she’s been hiding it.”

Dancing with the Stars airs Mondays (8 p.m. ET) on ABC.