It’s time to get down and Dirty 30.

The new house party-themed comedy starring Mamrie Hart, Grace Helbig and Hannah Hart hits theaters and digital platforms this week, but last fall, ET got an exclusive invite to the Los Angeles set.

“It's going to be super-duper fun,” Mamrie teases. “It'll be nostalgic. It will be that house party you wish you'd gone to in high school, but this one is occupied by a bunch of idiot adults.”

Mamrie wrote the movie, but it’s not exactly autobiographical. The 32-year-old says she embraces the aging process in real life. In the movie, not so much.

WATCH: Dirty 30 Is Here! Check out the Trailer

“My character, Kate, is about to turn 30,” she explains, “and she receives a letter from her high school self, that her teacher had her write to herself, and when she reads it, she realizes that her life isn't what she thought it would be, and kind of... you know, melts down a little bit and has her two best friends throw her a party.”

“I love, love, love a party movie,” Mamrie confesses. “One of my favorite movies of all time is Can't Hardly Wait … I've wanted to do a party movie, because I love parties myself, and it's a good place to do, like, multiple storylines.”

Hannah and Grace play Mamrie’s high school buddies, Charlie and Evie. They’re on their own journeys of self acceptance -- Evie is dealing with a unhappy marriage, while Charlie is figuring out the coming out process.

“There's a lot of different love relationships that happen in this film, which I think is interesting,” Grace says. “They all happen simultaneously, and in such a different way, but I think you'll be able to relate to at least one or two of them.”

“Grace is absolutely right with the little sub-romances that are happening throughout the film,” Hannah adds. “It's just an endearing kind of relationship-dynamic movie, all wrapped in a throbbing house party.”

“Throbbing?!” Mamrie asks.

“No, that really kind of emcompasses it,” Grace says.

“I like the intimacy of a house party, you know?” Mamrie shares. “Like, bars schmars. Like, I want to rifle through people's belongings, you know?”

“During filming of the party scenes themselves, we always leave each take like, 'We should party more!'” Hannah says.

The ladies last starred together in 2014’s Camp Takota, but don’t expect any nods to that film in Dirty 30.

WATCH: Grace Helbig Gets Candid in Grace & Style

“There's not really any Easter eggs,” Grace laments. “Well, I guess, like, an unintentional nod is, again like Camp Takota, we got to bring in a lot of our really talented friends to be in this, and play really ridiculous characters, and really showcase how talented they are, which is I think what we did on Camp Takota, and so getting to do it again is really fun.”

“Rhett and Link, they were so good,” she continues. “It was originally a character -- it was one person -- and when we found out that they both wanted to do it, Mamrie wrote it into two people.”

“'Dude' became 'Dude No. 1' and 'Dude No. 2.,’” Mamrie says.

“It was perfect,” Hannah chimes in. "A symphony of dudes. Does that sound weird?”

“That's the logline for the film,” Grace says. “Dirty 30, a symphony of dudes!”

“A symphony of dudes,” Hannah repeats.

“I think that emcompasses it,” Grace says.

Dirty 30 is out in select theaters, digital HD and iTunes on Sept. 23. 

ET was also exclusively with the stars at VidCon after they premiered the Dirty 30 trailer. Check out the video below to hear more about the film.