The London-born actress has been ever present in the Next Generation TV series and films, playing the half-human and half-Betazoid Commander Deanna Troi.
You're very different from your character. How do you remain very demure and meditative on screen?
It's a huge challenge to be true to the character. I have to keep Marina out of Troi. Because of the four-year wait this time, when I got back on set, too much of Marina had invaded. When I saw the premiere, after my first line my husband turned to me and said "When did Troi become English?" I'd lost her voice. It came back later in the movie, but the first line I had to say as Troi, she was gone, and it was Marina going [adopts cockney accent] "Hallo guvnor".
It's unusual to see Troi threatened directly, but in this film there's a sex scene in which Troi is actually violated in quite a sinister fashion...
It's not as sinister as what we actually shot. That was really horrible - it was more explicit. Tom [Hardy], Ron [Perlman] and I had to really go for it and then leave it up to the editors to cut out the bits that weren't suitable for children.
I gather most of the cuts made in the final edit of the film were character-based stuff...
It's interesting, I really loved the movie, but I think sometimes the movie-making element of Star Trek forgets that the series was successful because of the relationships between the characters - that's what the audience loved. Fans always say "we like your show the best because we can sense how much you love each other and it comes across on the screen". They were the scenes that were cut. This of all the Star Trek movies had the most time cut out of it.
If this is your last Star Trek movie, what won't you miss about the character?
The costumes. You wouldn't choose to wear what any of the girls wear on Star Trek. The only good thing about that series coming to an end after seven years was I could finally breathe. People say, as a woman, did it offend you to wear these skin-tight costumes? Absolutely not, because our biggest demographic is men 18-49. What are they going to put us in, a Hawaiian Muumuu?!