VidCon got Dirty this year -- and only ET was there to see it happen.

Mamrie Hart, Grace Helbig and Hannah Hart spoke exclusively to ET after premiering the trailer for their new movie, Dirty 30, at the convention in Anaheim, CA, last Friday. The film is set to hit theaters and on-demand platforms on Sept. 23.

“It feels so good!” Mamrie beamed. “It's actually the day before my birthday, and four days before Grace's, so we're going to, like, celebrate birthdays [and] a birthday movie when it comes out.”

“Yeah, we really get to leverage our birthdays as a means to get people to watch the movie, which is great,” Grace jokes.

“And I'm turning 30 this year, so I am also involved in this conversation,” Hannah chimes in.

WATCH: Grace Helbig and Hannah Hart on Getting Mystery Tattoos Together at 3 AM

In honor of the trailer’s debut, we had to get the ladies to spill some on-set secrets. First up: who got the wildest while filming?

“We, honestly, have this long-standing thing of being pretty professional on our sets,” Hannah admits. “We also shoot within really tight time constraints.”

“I mean, in character, I think Hannah's character is very competitive, and it shows at the party,” Grace teases. “I remember Hannah would be filming scenes that Marmie and I weren't involved in, and I would go check in on those scenes, and it had gotten to a very competitive place, emotions had escalated and she was 200 percent going for it.”

“Yeah, I have to,” Hannah confesses. “I compensate for my height with my intensity.”

Mamrie cops to having the most embarrassing filming moment.

“I don't want to do a spoiler,” Mamrie says, “but I definitely had to, like, pop a squat at some point. So, yeah, I won't say when or how, but that's fun to act.”

WATCH: Grace Helbig Tackles Beauty Culture

As for cameos that fans can look forward to, the ladies say Rhett and Link’s hippie partygoers and Drew Monson’s nude guest are total standouts.

“Grace's midriff is out, like, the whole movie,” Hannah adds. “It has its own credit.”

“Turns out I have a belly button, and it's in this movie,” Grace agrees.

And finally, each star chose one word to describe Dirty 30. Mamrie went with “rambunctious,” Hannah picks “romp,” and Grace says, simply, “fun.”

“A rambunctious, fun romp!” Mamrie summarizes. “We birthed it, and it has a belly button.”

You can check out the trailer for that rambunctious, fun romp in the video below.