Gillian Anderson was not eager to return to the small screen.

After her hit Fox series “The X-Files” ended its run in 2002, the actress, a graduate of DePaul’s Theatre School, turned down all television offers, preferring to concentrate on film and stage work. Even though she now lives in London, Anderson nearly declined the role of the mysterious Lady Dedlock in the acclaimed BBC-Masterpiece Theatre adaptation of Charles Dickens’ classic Victorian novel “Bleak House,” which debuts at 7 p.m. Sunday on WTTW-Ch. 11.

But the actress took the part, she says, after reading the “Bleak House” script, which is by Andrew Davies (who wrote the terrific 1995 television adaptation of “Pride and Prejudice”), and becoming intrigued by the complicated depths of Lady Dedlock, a seemingly cold aristocrat with a lot to hide.

Lady Dedlock “made a couple of choices that, in that day and age, had potentially devastating effects on her career as a wife and mother, which is what women were for back then,” Anderson noted in a phone interview. “As a result of that, she had to keep those … decisions very close to her and had to hold those secrets very tightly to keep [them] from destroying her life.”

“The consequence of holding those secrets and the loss that she experienced quite young, over time had a kind of viselike effect on her,” Anderson said. “She became very … constrained and tight and severe and outwardly judgmental and very, very sad.”

Anderson herself sounded anything but sad, especially when musing on the influence that the “X-Files” — and her character, the forthright, dignified FBI agent Dana Scully — has had on the television landscape.

“X-Files” creator Chris Carter, she recalled, “fought tooth and nail to get me,” rather than the kind of buxom, airhead female characters that were often seen on television dramas back then.

“Ironically, it had an international effect on women and on television and how women were not just perceived but how they behaved,” Anderson said.

She says she still finds it a bit hard to believe that “this funny old series we were doing had such a huge influence on the history of television in many ways — from the lighting on television, to the kinds of stories that [are] being told, to the characters” that are all over the prime-time schedule.

“The amount of things you see right now where they even just have a male and female as investigators. It’s almost a joke,” Anderson said. “It’s like, somebody should come with something different now!”

The complete text of my conversation with Gillan Anderson is below.

Why did you choose to take this part? Were you reticent about taking another TV role and the demands that that would make on your time?

“I think it had less to do with the demands on my time and more to do with just doing television, period. I’d turned down everything that had anything to do with TV since `The X-Files’ ended.

“But when I was offered this role [in `Bleak House’], I was told that [taking this TV role] was very different. I live in England and I was reminded that in England it’s much easier for actors to move between television and film and stage, all the time, whenever, and it doesn’t have a negative effect on their careers. It’s just part of their body of work.

“Then I started reading the episodes and they were so beautifully written and the episodes were so intriguing and the character was so intriguing and I got very much wrapped up in it. I met the director and the producers and it all made sense. It was something I really wanted to do.”

Can you describe Lady Dedlock and what about her made you want to take on the role?

“She’s an incredibly complicated and complex character. She lived a particular life at one time then made a couple of choices that, in that day and age, had potentially devastating effects on her career as a wife and mother, which is what women were for back then. As a result of that, she had to keep those — not mistakes — but those decisions very close to her and had to hold those secrets very tightly to keep [them] from destroying her life. Then, after she married, to keep them from destroying her life with her husband.

“The consequence of holding those secrets and the loss that she experienced quite young, over time had a kind of vise-like effect on her and the way she was in her world. She became very kind of constrained and tight and severe and outwardly judgmental and very, very sad.”

Was the challenge playing someone who was so guarded and constrained? Was that part of the challenge?

"No, I don’t think that was part of the challenge. There is, because of the amount of loss that she has experienced and continues to experience throughout the episodes — what was challenging was making those moments different from each other. If you continue to see her in a state of remorse or pain or fear or any of the things that she experiences in the course of the story, the challenge is to make watching that not a tedious experience.”

Did you see any parallels between Lady Dedlock and Lily Bart, the role you played in the film “The House of Mirth”? Did you see any similarities between the roles?

“It was even worse than that [for Lady Dedlock of `Bleak House’] because it was another half-decade before [the era of `The House of Mirth’]. The consequences for a woman were even more dire [in Dickens’ day]. But they’re very different characters. Lily Bart was a very naïve young woman, and Lady Dedlock is a very worldly and experienced woman. They’re quite different. I think Lady Dedlock’s secrets are even bigger secrets than Lily Bart’s secrets.”

You’ve been doing a lot of theater in London, is that what you prefer at the moment? Is that your biggest love right now?

“No, I mean, I’ve done two plays in London and now five films, so I wouldn’t say it’s my biggest love. But it’s certainly something I want to continue pursuing and do more of in the not-too-faraway future.”

Speaking of “The X-Files,” is that something you’re still recognized for?

“Mmm-hmm.”

Does it happen a lot? Is that a part of your life you’re excited about?

"I wouldn’t say it’s something I’m excited about, it’s just a part of my life. I get recognized on a daily basis, whatever country I’m in.”

Is that surprising to you, that you still get recognized so much?

“No, it’s not surprising. When it becomes surprising is when I feel like I look completely different from the character [laughs], and my hair’s up in a ponytail and I’m wearing flip flops and whatever. That’s when I find it surprising, when I think I’m incognito. Not that I try to be incognito, but when I just think that I dissolve into the background [but I don’t].”

Just talking a bit about Dana Scully, the character you played on “The X-Files,” I see all these women on TV now, strong women in law enforcement, working as various kinds of investigators. Do you feel that your portrayal of Scully or Scully as a character helped to bring that about?

“Well, it seems to be [he case]. That comes down to the creator, Chris Carter, and his vision of who this character was and [the person] he wrote and the episodes [that he created]. And that was basically the beginning of all of it [i.e., a change in how women were cast and portrayed]. He fought tooth and nail to get me rather than what used to be the version of women television back then, which was very different. And ironically it had an international effect on women and on television and how women were not just perceived but how they behaved.”

Yeah, I think you’re right. It’s good that the way women are depicted has changed for the better.

“It’s amazing. It’s amazing to think that it did [change]. [Laughs.] This funny old series we were doing had a huge influence on the history of television in many ways, from the lighting on television to the kinds of stories that were being told to the characters. The amount of things you see right now where they even just have a male and female as investigators. It’s almost a joke. It’s like, somebody should come with something different now!” [Laughs.]

Is there another `X-Files’ movie in the offing?

“Yes, we hope, all of us hope, that there will be one, but I think there are some complications right now with Fox. So who knows what’s happening. I keep being told it’s going to happen but then it’s not [happening], so I think it’s just in stagnation.”