Even if she’s not scoring as Supergirl until next year, Milly Alcock is flying high with “Sirens,” Thursday’s buzzy Netflix series.

“Sirens” scores as a lush look at the upper upper crust led by Julianne Moore’s guru-like entrepreneur Michaela and her billionaire hubby (Kevin Bacon) and the army of support they require from gardeners, drivers, cooks, maids and Alcock’s Simone, easily Michaela’s most devoted and driven assistant.

Simone’s new life as handmaiden to the slightly sinister Michaela prompts a surprise visit from her older sister Devon (Meghann Fahy of “White Lotus 2”).

“They’re trying to plan a gala over the Labor Day weekend,” Alcock, 25, explained in a phone interview, “and my sister Devon arrives and causes havoc. It’s about the unraveling of the weekend.”

Simone we discover is complicated, given to curating bits of her life into an alternate reality. Where did Alcock begin with someone so contradictory?

“I started by reading the script over and over again. We were sent the first three episodes (of 5), because Molly likes to write as she shoots. We didn’t actually know the ending until we were about halfway through filming.”

In that scenario, what guides you?

“Inherently, it’s your instincts. In terms of the overall arc, (creator, showrunner, writer) Molly (Smith Metzler) was always on set. Always asking us for our opinions, willing to change lines if we had questions about what things meant. She was always there.

“So I knew what was going to happen by the end, even if I didn’t really know how we were going to get there.”

Her meteoric rise getting to these starry plateaus?

“My big break was ‘House of Dragon’ as the teenage Rhaenyra Targaryen.

“Honestly,” she said of acting, “it was the only thing I was good at. I was — I’m serious! — a terrible student. I would try really hard and I would fail exams and was held back. Then I finally dropped out of school.

“The education system just never worked for me and my brain. I found acting was a great outlet. I had a lot of feelings as a kid, and I didn’t know where to put them. Acting was a place that I felt where I could be of value.

“So I was like, Oh yeah! I’m gonna make this work somehow.”

As to her career, “The older I’ve gotten, the more I’ve wanted to be a bit more savvy with my time. I don’t want to be a movie star. That’s not the goal.

“The goal is to be happy, make good work and just enjoy my life.”

“Sirens” streams on Netflix May 22

Milly Alcock as Simone, and Kevin Bacon as Peter Kell in “Sirens.” (Photo Macall Polay/Netflix)