“I made a real decision when I was, like, 11 that I wasn’t gonna be like a typical teenager,” says Bella Ramsey.

Talk about an understatement.

By the time Bella was 13, they had been cast in the world’s biggest TV show at the time, Game of Thrones.

And when the actor, now 21 years old, speaks to BBC Newsbeat, it’s the night after walking the red carpet at the London premiere of The Last of Us season two.

The smash-hit adaptation of the PlayStation video game was a critical and ratings success, launching the young star to full-on leading role status.

“I think it’s quite a unique experience,” Bella, who’s originally from Nottingham, England, modestly admits.

The rest of this article contains spoilers for The Last of Us season one.

Bella, who uses gender-neutral pronouns, plays Ellie in the HBO drama, set in a post-apocalyptic future where humanity has been almost wiped out by cordyceps.

The deadly parasitic fungus turns humans into zombie-like creatures, but Ellie is immune from infection and is humanity’s last hope for a cure.

In the first season viewers saw a father-daughter relationship slowly blossom between Ellie and mercenary Joel, played by Pedro Pascal.

After escorting the 14-year-old on a dangerous journey across the USA to meet doctors working on a vaccine, it becomes apparent Ellie must die for a potential remedy to be produced.

Rather than sacrifice her, Joel kills the medics and flees with the unconscious teenager.

When she awakes, he lies to her about what happened, and season one’s cliffhanger ending leaves viewers with the strong impression that Ellie is well aware of the deception.

So when the new season begins, five years later, “obviously there’s tension in that relationship,” says Bella.

“It was quite horrible to play.”

Young Bella’s vow to not be a “typical teenager” was actually less about their career and more about their relationship with their parents, they say.

No screaming matches, no slamming doors.

“So I never went through that with my dad,” says Bella. “Me and my dad are great.”

“So it was kind of sad to do that with Ellie and Joel.”

But, Bella adds, Ellie “is very justified in her feelings about everything”.

Ellie is 19 in season two, not too much younger than Bella, who began shooting the first series back in 2021.

Number two was delayed by the 2023 Hollywood strikes, so a lot has happened for Bella in the meantime.

There’s symmetry there.

“It’s so fun getting to step back into a character but with kind of new revelations about her and about me in my own life,” says Bella.

“There’s always like a merging of me and whatever character I’m playing and that happens times 10 with Ellie because I’m spending so much time in her skin.”

Bella’s recently spoken publicly about being diagnosed with autism while working on the first series of the show.

“It was something that I didn’t really think about too much before,” Bella starts.

“Actually, no, that’s a lie. I did, because I said that I was neurodiverse before, and then I was like, ‘Why don’t I just say what it actually is, which is, yeah, I’m autistic.”

Bella says opening up has allowed them “to be a bit more free” and hopes it will inspire others.

“You can be in industries like this and openly say that you’re autistic, why there shouldn’t be sort of such a stigma around that and such a fear around that,” says Bella.

“So I’m very proud to be able to say it out loud and also just to bring more awareness.

“Autism comes in all different shapes and sizes, and and I’m not someone that people would maybe typically see and go like ‘oh, you’re autistic’.”

Bella also identifies as non-binary, and the new series of The Last of Us more deeply explores Ellie’s same-sex relationship with Dina, played by Isabella Merced.

“I feel like we’re still figuring out how to portray queer storylines in the media in a way that feels very authentic but that also feels very genuine in terms of the story,” says Bella.

“That’s what The Last of Us does so well, I think, with Ellie and Dina.

“It doesn’t feel like it’s like representation added on top to check a box – it really feels like it’s just a part of the story.

“So that was what was exciting about getting to portray this sort of relationship in this medium.”

The Last of Us has already been commissioned for a third series after a positive critical reception for season two, so Bella – and Ellie – will still be growing up in the public eye for a while yet.

It’s something that “comes with pros and cons,” says Bella.

“But it’s kind of lovely that my growth and development has been immortalised on-screen.

“I feel very grateful for that.”

But Bella says there’s one thing that doesn’t get any easier.

“The more that you grow up, you just realise how little you know, I think. And I think that’s something that Ellie is also discovering.”

The Last of Us Season two launches on Sky and streaming service NOW on Monday 14 April.

Listen to Newsbeat live at 12:45 and 17:45 weekdays – or listen back here.