Were you a fan of Spooks before you joined the show?
"I'd watched the first couple of series, dipped in and out of it, but I think everyone's a fan of Spooks even if they don't watch it all the time. Every time I tell someone that I'm doing Spooks, they're like, 'Wow!' That's a guaranteed reaction. It's such a high-end show, it's so sexy and slick and smooth. It's got a great cast as well, so I'm chuffed to be on it."
Were you nervous about joining such a well-established show?
"I know this is the ninth series but they've got a lot of new cast coming in, so you don't feel like you're the only one. And I'm not a spy, I play Lucas's ex, so I kind of dip in and out. I'm in throughout the series but I'm not part of this mafia or that mafia, you know."
Can you tell us a bit about Maya?
"She's a doctor. She's Lucas's ex-girlfriend - they come back into each other's lives. She's the love of his life and he's the love of her life and they've got some unfinished business. All hell breaks loose really. It's very passionate, very unspoken, what they have. The minute they're back together again they can't control it - they just let it take its natural, organic course and it creates some serious problems."
You've got a history with Lucas - do things from his past emerge because of Maya?
"Yeah, stuff from his past comes up. He's not the person she thought he was. It's all very mysterious, very sinister, so all of that comes into play. But that's all part of what drives this relationship and what makes it so serious and so sexy. We've got a couple of very passionate scenes - kitchen worktops and all of that - so look out for those!"
Did you enjoy filming those scenes?
"I was dreading it. I've done Footballers' Wives and on that you go, 'OK, when am I getting my t*ts out this time? OK, who am I shagging next?' So you kind of get used to it. But that was all done with a lot of humour, whereas this is very passionate. There's no one better than Richard [Armitage] to do those scenes with. It is all very choreographed. It's not as sexy as it looks. It was frightening at first, but once you're on set you go, 'Oh, it's OK'. It's not like I've got my kit off and we're shagging each other."
So you managed not to laugh?
"Yeah. It's not funny at all!"
Do you get on well with Richard?
"Yeah. I met Richard a few years back in LA. I'd been starved of British company and I met him at Fox studios, and I was like, 'Oh my God, you're British', and I dragged him to lunch with me like, 'Sit here! Talk!' So bless him, he entertained me for hours. He was like, 'I do have a flight to catch...' It was great fun working with him, absolutely."
Can Lucas trust Maya?
"Definitely. I think he knows that. I think that's not even a question in his mind about whether he can trust her. For sure, definitely."
Does she cause any trouble?
"I don't know if she causes trouble. I just think that their relationship is so volatile and their relationship is so passionate that things are going to happen. They make decisions and they want to be together forever. Because of that there's trouble, but it's not because of her. It's just the circumstances that they're in and the fact that they have a strong desire to be with each other."
Spooks isn't worried about killing people off. Did you think about that at all when you took on the role?
"It's unpredictable. I had no idea whether I was going to be killed off or not. At the end of the day, you just know what the show's about. You know there's a chance that you could go, but you have to embrace that. That's what makes it exciting and that's why viewers tune in, because you don't know who's going to get blown up!"
You worked on Primeval before and said you couldn't really return because of being a mum. Do you miss that at all?
"I miss the cast and the crew. It's just so much fun doing that show and it's got such a huge fanbase, so yeah, I miss that. But I'm doing this and it's so much fun, and I did Sarah Jane Adventures, I did Conan The Barbarian - I play his mum! Because I'm not a spy in Spooks and I'm not in every day I'm able to do other things, which is great fun because it breaks it all up for me and I get some time to spend with my daughter. I'd have to move to Dublin for Primeval so it would have been a bit much."
The new series of Spooks begins Monday, September 20 at 9pm on BBC One.
Are you excited about the return of Spooks? Do you think Laila is a good addition to the cast? Leave your comments below!