Twenty-five years after she first appeared on the groundbreaking science-fiction drama The X-Files, actress Gillian Anderson is vowing that the 11th season - which airs on Thursdays at 9pm (Fox, Singtel TV Channel 330 and StarHub TV Channel 505) - will be her last.

"Because I've done it for so long and it's been an extraordinary journey with an extraordinary character," says the 49-year-old, who plays Dana Scully to co-star David Duchovny's Fox Mulder, two federal agents tasked with solving cases involving the paranormal.

"And there's a lot more that I want to do. I don't really want to be strapped down to something - I've got three kids and want to be as present for them as I can," says Anderson, who has a daughter, 23, from her marriage to former X-Files art director Clyde Klotz, and two sons, 11 and nine, with former boyfriend and businessman Mark Griffiths.

She spoke to The Straits Times and a handful of press in Los Angeles recently about her career-defining turn as Scully, which earned her an Emmy and Golden Globe for Best Actress.

Reflecting on how her portrayal of the iconic character has evolved over the years, she admits she knew nothing about acting when she first took on the role.

"I was so green, so everything that I did felt completely brand new and by the seat of my pants," says the British-American performer.

"Learning my craft was (done) very much in front of the public, including the mistakes I made. Sometimes I watch early episodes and you can see... there was ego in there. Until I found my way with it, you can see the trajectory of how I finally got comfortable with her."

Anderson - who has won raves for some of her more recent work too, including playing a detective on the noir thriller The Fall (2013 to present) - is still trying to work out how to play Scully as an older woman.

"The interesting challenge, after being away from her for a while and coming back, is how to make that same character show up as a 50something. And sometimes, I feel like I've figured that out and sometimes, I feel like I haven't."

As a public figure, though, the actress seems to have things figured out.

She has grown increasingly outspoken over the years about the many causes she champions, including women's rights.

Unusually for the female lead of a major series, she has openly called out the unfair treatment of women behind the scenes, revealing, in January 2016, that the TV network initially offered her only half of Duchovny's salary when they decided to revive the series that year and that she had to fight for wage parity.

Last June, she spoke up again, tweeting that only two out of the 207 The X-Files episodes had been directed by women at that point and that she looked "forward to the day when the numbers are different". A few months later, creator Chris Carter announced he had assigned two female writers and two female directors to the current 10-episode season.

Asked what advice she would give to other women fighting for equal pay, however, and she sensibly notes that most of them are not in the enviable spot she is in.

"I am in an extraordinarily privileged position where I get to say, 'You either pay me the same or I'm not doing it', which means they don't have a show.

"My version (of this) does not equate to pretty much everybody else's, where their livelihood is on the line and the stakes are so much higher. So I'm not, for a second, going to approach, 'How do you talk to your boss?' I have huge respect for anybody who has the balls and courage to stand up and say, 'This is not fair.' Because the consequences can be great."

Ask her why more actresses in her position have not spoken out against gender bias on their shows, and she has another measured response. "I think they have. The thing is, (in The X-Files), the disparity is so extreme, it's easy to talk about," she says.

Still, "I'm sure that fear plays a part" in some actresses not speaking out.

"It's also maybe that it's not necessarily at the forefront of people's minds. Actors are very focused on their work and they may not have noticed that there weren't female directors - we're so used to being directed only by men. I know a lot of female directors in the industry who have tried for years and years to get work, and they're only starting to," she adds. "But now, it's trendy to hire female directors."

She is heartened by the groundswell of awareness this year following the #MeToo and Time's Up campaigns highlighting the sexual and other abuse women experience, along with Hollywood's efforts to do more about it.

"I think finally... we are at the beginning of a much more well-rounded environment in this industry in terms of not just women, but greater representation for everyone," says the star, who is in a relationship with British screenwriter and playwright Peter Morgan, 54.

And in the economy as a whole, "now it's a big-enough, loud-enough conversation that there's starting to be some policy change and accountability".

She adds: "Women and men are at the forefront of making sure there's a shift taking place inside big business, small business and our industry. And hopefully it will become easier for everybody to be able to have conversations about fair practice."

•The X-Files airs on Thursdays at 9pm on Fox (Singtel TV Channel 330 and StarHub TV Channel 505).