Yellowstone's Kelly Reilly Borrowed One Key Beth Dutton Part From Kevin Costner

Kelly Reilly is definitely one of a kind — and so is Beth Dutton, whom she played for years on "Yellowstone" and will soon portray on a spin-off series centered around her character. But there's something about Beth that made her even more distinctive — her accent. While appearing on The Drew Barrymore Show, Reilly confessed that she got her character's accent down pat by listening to "Yellowstone" star Kevin Costner speak. 

Admittedly, the tone Reilly uses as Beth isn't pure Costner. She added that Beth's smoking — a character trait that she can't stand – encourages her to use a certain register, as does Beth's fondness for booze. "She's educated, she's from a very very wealthy branch of the family," Reilly said. "For Beth it was more about the voice ... I kind of listened to Kevin a lot, because he really deepened his voice for John Dutton. So I just stole it, I copied him."

Reilly also credits her dialogue coach with helping her shape Beth into the woman she is. But why does Kelly Reilly have to be so conscientious of the way she speaks when playing Beth? Because she isn't American.

As Kelly Reilly explained to Drew Barrymore, she's actually British, and gets help from dialect coaches to portray non-English ladies. She got her start on European television, in dramas like "Bramwell," procedurals like "The Ruth Rendell Mysteries" and miniseries like "Wonderful You," using her natural British accent in most of them. After that, Reilly broke into the movie market with 2005's "Pride and Prejudice," where she plays Caroline Bingley, the snobbish sister of Charles (Simon Woods). From there, she was required to put on American tones now and again, and sometimes try to reflect the cadences of characters from other lands. 

Since then, Riley has mastered a number of accents and dialects, including western, southern and Atlantic. But sometimes she still speaks with an English inflection for certain film or television roles. In any event, Reilly definitely knows how to properly portray all-American hellraiser Beth with authority — whether or not she's letting her co-stars' speaking patterns rub off on her.