In Only God Forgives, she plays Crystal, the blonde mother to two American, Bangkok-based sons - Julian (Gosling) and Billy, whose Thai boxing club is a front for drug smuggling. After Billy rapes and murders a teenage prostitute, he is killed in revenge. When Crystal turns up to collect Billy's body and Julian tells her what Billy did, she replies: "I'm sure he had his reasons."
Crystal seeks vengeance and loses control as the plot unravels.
'Crystal's pure evil," Winding Refn explains with relish. "It's like in a fairy tale where you have the queen bee, the insect that devours. Also, I was so used to making films about violent men, but here was an opportunity to bring in a woman as the real antagonist. This makes it much more complicated because it wouldn't just be another physical confrontation. Of course she has hypnotised her son to the extent where she fully controls his hands."
"A lot of the stuff that I had to do as Crystal was exciting and frightening at the same time," Scott Thomas says. "It made this whole project one of terror and at the same time totally thrilling."
The role came with the the kind of harsh, hilariously cruel dialogue actors dream of. But Scott Thomas says that though it was an interesting acting challenge "it was such a nightmare".
"After a while, once you've been doing this for a long time weeks and nights you feel, 'Oh, god, I'd love to say something nice,"' says Scott Thomas.
"It gets to you once the novelty of the transition is over and you're just stuck in that darkness."
Critics at Cannes had mixed reactions to Only God Forgives (it drew boos from some) and reviews for the film have been mixed. But Scott Thomas' performance has been hailed for its departure from her usual roles.
The experience, though clearly enthralling for Scott Thomas, was also unnerving. She exhales: "I'm going to do a comedy next."
Who: Kristin Scott Thomas
What: Only God Forgives
When: Opens at cinemas today
Follow @nzherald_ent on Twitter for all the latest entertainment news.
- TimeOut / AP