Along with the rest of the season one cast, Lucy Brown has returned to Primeval – despite her character Claudia Brown disappearing at the end of the first season. She makes her mark as PR professional Jenny Lewis, the antithesis of Claudia, as she explains to Paul Simpson...

Does it feel very strange playing a totally different character this time?

Stranger than I thought it was going to be. When I got the brief about what was going to happen with Claudia, it was really great to be able to come back to a show that I love and then to play something completely different.

Coming on set, I was so familiar with the rest of the cast and with the premise, and I had to try to put that to the back seat and go, "Hang on, I don't know any of you, what any of you like or dislike, what your rhythms are, how I feel about different people..." To come in every day and try and see it with new eyes was an absolute challenge.

Are you really vamping it up for this series?

The way you walk and behave in outfits like Jenny's definitely helped because it's obviously such a completely different direction to Claudia. The heels got a lot higher, the hems got a lot shorter, so you can't help but feel very different. It's plainly not Claudia.

Was it a lot more fun?

It was different. I have a very strong attachment to Claudia, I loved her.

Did you play Jenny as an "evil twin"?

She's not an evil twin. I hope when people watch her, they'll fall in love with her in a different way. She's very sharp in whatever element she's in. She's dynamic, holds no prisoners – but not in an aggressive way or "evil" way.

We met Claudia coming up in the ranks, trying to find her feet. This woman is walking in at the top of her profession. She's awesomely good at it, and she knows it.

Did you base her on anyone?

I've got a couple of school friends who went into PR, and before we started filming I went into their agency for a few days. There were a couple of girls who I took bits from. The dress that I walk in at the end of episode one - I took a photograph of the girl at the office who was wearing a black dress with a red belt and high heels. When we came to do the costume, I put this down, and said, "I know who this woman is..." and we tried to match it really closely.

Does Jenny provide the love interest again for Cutter?

It's a very difficult situation. Obviously I'm coming back looking and sounding exactly the same as someone he was in love with. There's a natural chemistry that builds up between them, and she has weird flashes of "Why am I feeling very drawn to this person?"

She goes from "I'm here to do a job" to becoming more and more involved as the series goes on. There's a sense of déjà vu, and flashes. When we meet Jenny, she's engaged: she has a whole life in place that slowly falls away as the storyline continues.

How does she get on with Cutter's ex-wife Helen?

She only encounters Helen at the very end. She's heard of her, she's done her research from Lester, and got the whole thing: these are the problems, this is the ex-wife etc.

But I'm not approaching her as Claudia, I'm approaching her as Jenny, who's probably a little bit more similar to Helen in terms of, "Are you backing down? Because I'm not!" As opposed to Claudia who went, "Well, you are his ex-wife so..." It's quite an interesting standoff when Jenny and Helen do meet.

Do you get more recognition as a result of the first series?

Definitely, because it's obviously a very accessible show and lots of people watch it. For me, it really came towards the end when I disappeared. I wasn't prepared for the number of people who asked where Claudia had gone. It was fantastic: we've all spoken to people generally about the show, and it's all been so positive.

When did you know that was going to happen to her?

Immediately, when I signed on. I knew where the storyline was going, and I knew I was going to be involved in the second series, so for me the interesting part was where they were going to take it.

Of course, during the first series, ideas were still buzzing around. It was a really exciting time. I think the way they've written Jenny through this is incredibly interesting. The format has been shaken up in the second series and no one is quite what they seem. Just when you think you feel comfortable with where a character is going, it takes a sharp left turn.

What was it like filming at Battersea Power Station?

That was so brilliant. I've lived in London for a long time, and it's a building you pass, admire and wonder what's inside. It was fantastic going in there. Amazing – you can point the camera anywhere and it's fabulous. Except that I was in this tiny little dress, so I actually froze during most of it!

Do you have many action set pieces?

Very much so. The last few weeks the storyline is myself, Naomi [Bentley], Andrew [Lee Potts] and Hannah [Spearritt] getting caught up into something horrific, so we spent a lot of time towards the end of the shoot panting!

Is it as physically demanding as it looks?

Yes it is. Filming anyway, no matter what you do, you need to be in pretty good shape because of the hours that you put in and the lack of sleep.

Is there a good camaraderie on set?

Very much so. We were on this crazy set at the end of the shoot, with smoke and lighting, and Naomi has these fabulous personal photos of us all on set doing Michael Jackson walks.

Do you get anxiety dreams about dinosaurs?

I dream about work every night that I'm on set because it's such a massive part of my day, and a series like this is just so vivid. I think I should still be on the payroll!