Phyllis Logan: 'It's exciting to have one last hoorah for Downton Abbey with the movie'

1. How would you describe Switzerland in five words?
Intelligent, funny, intriguing, thought-provoking, shocking.

2. How would you describe Switzerland in more than five words?
It's a brilliant psychological thriller about the award-winning popular writer Patricia Highsmith – but if you aren't aware of her work it doesn't matter. Joanna Murray-Smith's writing engenders the curiosity of the audience to know more about this eccentric character – her play does all the work for you. It piqued my sister's interest for example – she loved the production and then went and bought a lot of the Tom Ripley series of books.

3. How would you describe your character, Patricia Highsmith?
Very complex, highly intelligent, she has a wonderful way with words. She's quite mean also, doesn't suffer fools gladly. Her personality and character could appear harsh and abrasive but then in her writing she shows extraordinary humanity. She's a very complicated character.

4. Did you find it harder or easier to play a character who is based on a real person?
I tried not to think about that or you'd become obsessed with "am I doing it 'right'?" She died in 1995 you see, so you can never really know, but I was reading into what her contemporaries and other people said about her. Ultimately you read what's on the page in front of you, Joanna Murray-Smith has written a fabulous play about her so I have to get the truth from what's in her script.

5. Did you know much about her before you began the show? What did you find out about her?
No I didn't – I knew OF her of course but not in much detail. I found out all the above through my research. Like for example that she had a capricious nature. She had a liking for snails – she would on occasion take them out for dinner in her handbag.

6. Did you jump at the chance to play Patricia Highsmith?
Oh I did. As I say I knew the merest details beforehand but I read the play and thought 'Oh god this is something I'd love to do'. It was Joanna's play that caught my imagination.

7. Are you a fan of her novels?
In the spirit of research I have read The Talented Mr Ripley, Stangers on a Train, her biographies. She's quite dark. Hitchcock turned Strangers on a Train into a movie but her book is much darker than the movie portrays.

8. What do you enjoy the most about starring in this production?
It's been great to get my teeth into this fantastic character. And playing alongside Calum Finlay – he's a lovely bloke. With an hour and a half straight through on stage together we spark off each other and that's a big plus.

9. What must there be in a two-hander acting relationship?
Definitely trust – and you have to like one another – which we do! To be on the same page, it's so important. While we were rehearsing the production at Theatre Royal Bath earlier in the year, before we got into the proper swing of things, there were times I would just stare at him not knowing what was supposed to be coming next and he'd always rescue me.

10. What do you find hardest about performing in this show?
Oh the stamina – you have to gird your loins and go for it! The production is zippy and fast-paced; we have to be on each other's cues straight away.

11. What's your earliest memory in entertainment?
Primary school, one of our little nativity plays. I was Mary – I remember I was one of the main players even at a young age.

12. What do you consider to be your big break?
I'd have to say Another Time, Another Place. The movie was adapted from the novel by favourite writer, Jessie Kesson. I won a BAFTA for Outstanding Newcomer to Film.

13. What would you have been if you hadn't become a performer?
A vet.

14. What is it that draws you to acting?
It's lovely to sink into another world, another character.

15. Who are your idols?
I don't go into idolatry but I do admire my husband, and my son.

16. If you could go back in time and change one thing, what would it be?
That implies regrets and I don't dwell on them.

17. Was working on Downton fun? Were you surprised at how successful it was?
It was enormous fun and I was very sad to say goodbye – which is why it's been all the more exciting to regroup and we have one last hoorah with the movie. If any of us knew the secret of its success we'd all be squirreled away in our studies writing away at the next big hit!

18. What do you do to unwind in your spare time?
Watching documentaries – my husband and I love watching David Attenborough's Blue Planet and so on

19. What would your dream role be?
I think I'd have to say this is my dream role. Playing a wonderful character in the West End premiere production.

20. What advice would you give to aspiring actors?
It has to be something that you really, really want to do – you really have to question that. But if you do then just go for it. Just keep plugging away.