Candid and determined, British actress Anna Maxwell Martin is the real deal

“More recently I’m trying to learn not to say everything that comes into my mouth,” she laughs. “I’m really known in the U.K. as having no filters.

“When there’s something live or I get asked a lot to be on these celebrity (talk) shows, sometimes I just want to hear my agent have kittens on the phone because she’s so worried about what will come out of my mouth the first 15 minutes of the show. I’m trying to install some filters into mouth and brain. I’m only semi-successful,” she said, giggling.

Her candid attitude has gotten her into hot water before. Like the time she admitted she’d shoplifted to a local publication, a tale that found its way to the infamous British tabloids.

While she’s a truth-teller in real life, the same applies to her work, says Martin, who’s dressed in a black sleeveless turtleneck and black pants. “In that moment of acting it’s about real relationships and not faking it,” she says. “If it’s emotional, it has to feel real. It has to come from a real place.”

Finding that “real place” has been Martin’s life work. She’s costarred in shows like “The Bletchley Circle,” “Line of Duty,” “The Frankenstein Chronicles” and her latest, “A Spy Among Friends,” streaming on MGM+.

Martin plays an MI5 agent who’s trying to get to the bottom of the notorious defection of double agent Kim Philby to the Soviet Union. Philby (played by Guy Pearce) has not only betrayed his country he’s deceived his best friend, Nicholas Elliott, (Damian Lewis) a fellow agent.

Martin says it was their relationship that attracted her. “For me it’s not about the spying nature, it was about the brilliant relationships. It’s really simply about a male friendship, and for myself and Damian, it’s a relationship where two people completely underestimate each other, and they get to a place of complete compatibility and understanding.”

The 45-year-old performer says she never thought of doing anything else but acting. “I don’t remember making a choice,” she shrugs. “I just thought that’s what I was going to do. And I sang when I was young, and then I started acting; just never wanted to do anything else. I don’t think I’m capable of doing anything else that’s practical.

“When you go to school you’re sat down and given career advice. ‘I want to be an actor.’ They said, ‘Can we think of a more sensible occupation?’ So I found myself choosing to do a week on an archaeology dig, scrabbling about in the mud. Very, very cold and I thought, ‘This ain’t for me. I’m going to go back to the original plan. It’s way, way easier.’”

Once she made the decision, she had no reservations about performing. “I never doubted I could do it. Why would I? I mean, this is what I want to do, I’m not going to sit around fretting about not being able to do it. I’m not that kind of person. I’m not very introspective. I’m not hugely negative.

“I’m a bit of a fish swimming around the goldfish bowl. I just forget and think about the next thing. I just thought, ‘This is what I’m going to do.’ And I think I’m good at it.”

For a long time that was her major aim — until she became a mother 13 years ago. Now the parent of two daughters, 13 and 11, she says that’s her full-time job. “I love my job. But I’m a mum before anything else. Now being a mum is much more important than anything else.”

Her husband, director Roger Michell, died two years ago. And though they’d been separated, it’s still a blow, Martin admits. “I had a big cry the other day going through Roger’s stuff. You find things that the children have made with him, and I had a big cry. And my first thought was, ‘Oh, I must get a grip.’

“And then it was, ‘Have a big cry now. You’re allowed.’ You get hoodwinked by it all the time. Grief, it swoops in like a black shadow and you don’t see it coming, do you? And I think you have to allow yourself. It’s been hard to say to my children it’s not going away. Because time isn’t a healer.”