PARK CITY, Utah (AP) 鈥 "Whosa国际传媒 that girl?鈥 was a common refrain from Sundance Film Festival goers walking out of 鈥 My Old Ass 鈥 in January.

The comedic and heartfelt coming of-age-film, in which a small town 18-year-old eager to leave for college is suddenly in conversation with her 39-year-old self (thank you, mushrooms), was one of the breakouts of a strong festival. Itsa国际传媒 currently playing in select theaters, and will be in wide release on Sept. 27.

The girl in question is its vibrant star, Maisy Stella. Itsa国际传媒 a name that will be familiar to some, for her years on the television series 鈥淣ashville鈥 playing Daphne Conrad, for her viral video singing with her sister, Lennon Stella (31 million views and counting), and for being someone . But to a certain subset of cinephiles, Stella seemed like a complete discovery and an exciting one at that.

Both designations work, in a way. Stella is reintroducing herself in her first film role after taking a few years off to just be a normal teen. She started on 鈥淣ashville鈥 when she was 8 years old. At 15, she took a break from acting.

鈥淚 went back to school and made sure my head was like nice and screwed on and just went to prom and did all that stuff,鈥 Stella, now 20, said in an interview with director Megan Park earlier this year 鈥淭he second I turned 18, I was just like, I missed it so much and found such a new appreciation for it.鈥

In 鈥淢y Old Ass鈥 she plays Elliott, a bisexual teen on a small cranberry farm in Canada who is ready for her life to start elsewhere. But her 39-year-old self, played by Aubrey Plaza, tells her to slow down a bit, to appreciate the things around her in the moment and to stay away from a guy named Chad. Itsa国际传媒 a part that many actors wanted.

鈥淚 think the best thing she ever did was take a break for a second after 鈥楴ashville鈥 and just, like, be a normal human,鈥 Park said. 鈥淎 lot of kids that have been acting from such a young age, thatsa国际传媒 the only thing they know, and they don鈥檛 have as much life experience. And Elliott is just like a normal girl. Maisy has that perfect mix 鈥 she is one in a million.鈥

Park met Stella through their mutual friend Maddie Ziegler, who plays one of Elliottsa国际传媒 friends in the film.

鈥淚 think about her and Maddie and I鈥檓 like 鈥榮o it was like two 8-year-old prodigies just hanging out,鈥欌 Park laughed. 鈥淵ou singing and her just cha卯n茅-ing across the floor.鈥

Stella downplays this, as she does many things (we鈥檒l get to Eilish later). She and Ziegler, the 鈥淒ance Moms鈥 alum and Sia music video star, are just best friends. Their extracurricular talents don鈥檛 come up very often. But they do get to perform together in this movie, alongside Kerrice Brooks. Without spoiling too much, there is a bit of a dream sequence in which Elliott performs Justin Biebersa国际传媒 鈥淥ne Less Lonely Girl.鈥 Itsa国际传媒 a song that Stella suggested, and that Bieber and his camp had to approve.

鈥淚t was a big deal for our generation,鈥 said Stella. 鈥淚t like changed who I am today as a person.鈥

The film as a whole was a dream re-entry for Stella to work on material that she loved with a supportive group, including 鈥淲ednesday鈥 actor Percy Hynes White and Plaza, who was only there for a few days but made a big impression.

鈥淪hesa国际传媒 the most legit and the most genuinely profound actor,鈥 Stella said. 鈥淪he genuinely taught me so much about how to be a good scene partner.鈥

Plaza would ask what she needed from the day and then afterward make sure to text and give her a boost, saying how well she had done.

鈥淚n future projects like I will take that with me and like always try to give other people what she gave to me,鈥 Stella said. 鈥淚t literally made the biggest difference.鈥

Both Park and Stella were overwhelmed by the response to the film at Sundance, where it was quickly acquired by Amazon MGM Studios (for a reported $15 million) for a theatrical release. Stella, too, was already fielding opportunities.

鈥淪undance changed me,鈥 Stella said, a few months later. 鈥淭he experience of it woke me up in such a crazy way鈥 and auditioning for things feels a little bit more exciting when I feel like theresa国际传媒 a little bit more buzz or like theresa国际传媒 a little bit more of a chance that I will be like taken seriously.鈥

In the spring, she joined Anne Hathaway and Ewan McGregor in an ambitious (and top secret) film from Bad Robot, Warner Bros. and 鈥淚t Follows鈥 director David Robert Mitchell.

鈥淚 think this early on, getting to do two projects that are so opposite is like winning the lottery,鈥 Stella said a few months later during production. 鈥淚 am so aware of how special that is and getting to show any type of range is really exciting for me.鈥

None of this is surprising to Park, who knew she had a star on the rise.

鈥淢aisiesa国际传媒 such the real deal,鈥 Park said. 鈥淪hesa国际传媒 been very patient and specific鈥 I think everyonesa国际传媒 really excited to see, at least I鈥檓 excited to see your long career and what you choose to do, because you鈥檝e been silently influencing so much of culture.鈥

Stella: 鈥淥h my god.鈥

鈥淏illie Eilish became a singer because of Maisy. I know this for a fact. Finneas confirmed it,鈥 Park said.

鈥淪he would have done it with or without me. I鈥檓 not the reason for Billie Eilish鈥 She is a genius,鈥 Stella said.

Park: 鈥淚鈥檓 your hype woman.鈥

Stella: 鈥淵ou really are, to the point where I just sweat.鈥

鈥-

as part of The Associated Presssa国际传媒 coverage. It has been updated with details about its acquisition, release and Stella's new project.

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