CANNES, France (AP) -- To convince Kristin Scott Thomas to play the bloodthirsty matriarch of "Only God Forgives," director Nicolas Winding Refn appealed to Scott Thomas -- how else? -- with the flattery of his own mother.
"That's how he got me to do the film," Scott Thomas said in a beachside interview Wednesday. "He said, 'You're my mother's favorite actress.' So I had to. It was a good trick."
It was an appropriate start for a disturbing portrait of a woman with, to say the least, harsh motherly instincts. In the Bangkok noir, which premiered at the Cannes Film Festival on Wednesday, Scott Thomas plays a mother demanding her surviving son (Ryan Gosling) avenge the murder of her other, more favored son (Tom Burke).
It's a ferocious, gloriously evil performance as far away from "The English Patient" (and the other elegant British period dramas Scott Thomas is best known for) as cinematically possible. Upon learning her son was punished for killing a teenage prostitute, for example, she retorts: "I'm sure he had his reasons."
"A lot of the stuff that I had to do as Crystal was exciting and frightening at the same time," Scott Thomas said. "It made this whole project one of terror and at the same time totally thrilling."
"Only God Forgives" is Refn's second collaboration in a row with Gosling, following the more pop "Drive." It's a menacing descent into brutal darkness, punctuated by bloody spurts of stylish violence. There's even less dialogue than "Drive" (the script was a sparse 60 pages, Refn says), and the film unfolds as a perverse Greek tragedy transported to Thailand's grim underbelly.
Refn conceived of Scott Thomas' character as a combination of Lady Macbeth and Donatella Versace after the actress sent him photos of her with long blonde extensions.
"I was like, 'God, that's so sexy,'" the Danish director said sitting alongside Scott Thomas. "That whole Donatella oddness: frightening but very sexual."
Scott Thomas calls the thick makeup an "ultra-costume."
"It's a sort of armor, that look," she says. "It's very, very, very empowering and at the same time very frightening. It changes the way people look at you completely."
While critics at Cannes had mixed reactions to "Only God Forgives" (it drew boos from some), Scott Thomas' performance was hailed, along with predictions of an Oscar nomination. In a memorable dinner party scene, she cuttingly and vulgarly dresses down Gosling's character. She negatively compares the size of his genitalia with his brother's -- an explicitness that not even the Greeks dared.
"They had all these things that were implied," Scott Thomas says. "I said why don't we just say it? Just get it out there, so to speak. Say the words that everyone else is alluding to."
Refn gradually cut the lengthy scene more and more until it was basically a monologue. Gosling also added a suggestion -- a slur Crystal lobs at her son's female guest -- after Refn asked for one of the most offensive words to call a woman in America.
"I couldn't get it out," Scott Thomas says, laughing. "I couldn't get it right until about 10 takes."
It's the kind of harsh, hilariously cruel dialogue actors dream of. But Scott Thomas says that while it was an interesting acting challenge "to push the dialogue," ''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. "This hatred and anger and destruction is actually quite difficult after a while. It gets to you once the novelty of the transition is over and you're just stuck in that darkness."
Much of the character and her archetypal qualities weren't refined until they were on set shooting. Refn works collaboratively with actors, guided by the boldness of his oft-repeated mantra: "The enemy of creativity is good taste." He was enamored by what "KST," as he calls her, did with the part.
"Most of the time, we'd just sit and stare and go, 'Oh my god! What have we unleashed?'" Refn says. "It was what the film needed, the film needed a character like that that would essentially be the antagonist of the protagonist. But she would be so dominating that you could never live up to her, you could never penetrate her."
The experience, while clearly enthralling for Scott Thomas, was also unnerving. As much as audiences at Cannes responded to her performance, she exhales: "I'm going to do a comedy next."
Follow AP Entertainment Writer Jake Coyle on Twitter at: http://twitter.com/jake_coyle