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Ella Jay Basco describes herself as one of the "relevant, not relevant kids" in her Los Angeles charter school. "If that makes sense," she adds. In a weird way, it kind of does. At 13, Basco is relevant enough to have her face plastered across billboards on Hollywood and Highland; but she insists that she's also not relevant enough to be treated any differently by her classmates because of it. Red carpet premiere or not, there's still homework to be done and algebra to learn. "There should be a photo somewhere of me in a big dress looking at a math textbook," she says with a laugh.

For Basco, this pendulum swing between "relevant" and "not relevant" is her new normal. The star of Cathy Yan's explosive Birds of Prey, she's forging a path for herself as a teen actor in an industry that rarely gives young, Asian-American women a chance to see themselves depicted as big-screen heroes. In many ways, that's what made Basco, who is Korean-Filipino, want to be part of the project. She was 11 at the time, and all she knew about the top-secret film was that it was "rated R with a female director" attached.

"I think what was super important was that it was an Asian-American female director, and it sounded super interesting, too," she tells MTV News over a chai latte. "They couldn't explain much about the film or the project [at the time], but hearing that it was a female director, that was super important for me because representation is so important."

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Jurnee Smollett-Bell, Cathy Yan, Rosie Perez, Mary Elizabeth Winstead, Margot Robbie, Ella Jay Basco, Chris Messina, and Christina Hodson at the world premiere of Birds of Prey in London

After a month of auditions, including chemistry reads with co-stars Margot Robbie and Jurnee Smollett-Bell, Basco landed the coveted role of Cassandra Cain in Robbie's anticipated "Harley Quinn spin-off movie." It was her first feature film. She then started her training, learning sleight of hand and diving into the comics to familiarize herself with Cassandra's storied DC history. "I bought a big stack of comic books," she said. "I wanted to read about her origin story and the relationship she has with Barbara Gordon's Oracle." But Yan and screenwriter Christina Hodson made things clear from the jump: This was a different interpretation of Cain — a character who's worn Batgirl's coveted cowl — than we've seen or read before. She's a smart-mouthed pickpocket, a foster kid scraping by thanks to her own savvy. She's also the catalyst for bringing all of these colorful characters together.

"She is definitely an outlaw in Gotham," Basco says. "She's a little sneaky and, at the same time, misguided and vulnerable because she doesn't have any parents. She's an orphan, and she really relates to all of these characters like Harley and Dinah Lance and Renee [Montoya], and they see a part of themselves in Cassandra Cain. And that relationship was super interesting to play."

The relationship that develops between Harley and Cassandra is integral to the story. It opens up a vulnerable side to Harley, a manic character known for resorting to extremes — blowing things up, siccing her pet hyena on bad men, laughing in the face of mayhem. For the first time, Harley has a protégé, someone she feels responsible for. Similarly, Cassandra finds a mentor in Harley, someone to look up to, not for her morality but rather for the way that she manipulates the system in her favor and takes what she wants without asking for permission or forgiveness.

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To establish that chemistry, Robbie and Basco "hung out a lot together." They also spent a lot of time between scenes rapping along to Cardi B ("I Like It" was a favorite on set) and having impromptu dance breaks. Robbie became something of a "big sister" to the young actor. "It definitely did feel like a sisterhood bonding relationship because she's just so nice and such a great role model," Basco said, adding that their friendship was solidified with a secret handshake that only the two of them know.

And then there was the group chat with the entire cast, established by Yan as a way to keep in touch with her Birds. "It's called The Birds, [and] we just send random photos to each other sometimes or I remember one time Rosie [Perez] was like, 'I had this weird dream. Everybody was in it. We were all dancing.' Everybody's so funny," Basco says.

But that was just the kind of set that Yan fostered. There was warmth, laughter, diversity, and badass women doing badass stunts. While Basco didn't get to contribute to the film's climactic fight sequence between the Birds and Black Mask's Gotham-dwelling henchmen ("Cassandra's still just a kid," Basco says), she learned the fight choreography anyway. "Just seeing them in action right in front of my face was really cool, and something that I definitely have never seen before… It made me feel like I could do this, I could really go out there and be who I want to be."

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As for the set, "It was super collaborative and comfortable," Basco said, touching her gold "Cass" necklace, a personalized wrap gift from Yan. Once a Bird, always a Bird. "There was no ego. She really made the environment super welcoming, and it was such a supportive and kind experience. She definitely made sure that everybody was represented too. I mean, whether it was onscreen or off, cast or crew. It was super cool to see more people who look like me."

"I feel like I was spoiled to have this first experience with all of these women in the cast and crew," she adds. "Unfortunately, it's not going to be like this every time, and a lot of films don't have a lot of women [on set]. But Cathy and Margot definitely taught me about being in the industry and knowing your worth and knowing your goal."

Acting is a goal she's had since she could remember. Her entire family is in the industry. Her father is an actor and her personal acting coach; her mother is a manager. Two of her uncles are also actors. Her uncle Dante, who starred as Rufio in Steven Spielberg’s Hook, tells her not to grow up too fast, to relish being a kid because she has her whole life to be an adult. Her grandfather, affectionately called Papa, went to all of her fittings (and had very strong opinions, she laughs). "I wouldn't be here without them," she says. "They really helped me build a thick skin because being part of the industry, you have to have that thick skin. Going into it, I definitely knew that there would be people telling you 'no' because you look a certain way or you have a different colored skin… but I think that's changing. To be part of that movement is inspiring."

One could say it's also extremely relevant.