Andrea Mandell

USA TODAY

BEVERLY HILLS — Riley Keough can't keep a straight face.

Sitting for a photo shoot the actress manages a few alluring shots, as her new Starz series, The Girlfriend Experience, would suggest, but her publicist and stylist keep making her laugh. "You guys!" she says.

But on Sunday (Starz, 8 p.m. ET/PT; all episodes on Starz.com for subscribers), Keough's new show will prove serious business, focusing on the most elite level of the world's oldest profession. The 26-year-old actress takes on escort duties in the new 13-episode series, loosely based on Steven Soderbergh's 2009 movie starring Sasha Grey.

Unlike the film, the series turns back the clock: Keough plays Christine, a law school student lured into the high-class escort world through a girlfriend.

Soderbergh, an executive producer on the show, says he told writer-directors Amy Seimetz and Lodge Kerrigan to take his title — and start from scratch. “We agreed that unlike the film, where you kind of parachute into a character’s life as a GFE, that it would be interesting to sort of set a character up and watch her gradually move her way through this world,” he says.

She tries sleeping with (mostly older) men for money — and later, revels in it. “I liked the idea of showing a girl who doesn’t come from an oppressive background, who is intelligent and has a lot going for her, that ends up in sex work. Not the other story, which has been told before,” Keough says.

As a character, Christine is “controlling, she’s manipulative, she’s selfish. She likes sex. She doesn’t really want to discuss her feelings or emotions. She’s more of a character you’d see for a male lead,” says Keough, who had zero nerves about the required pay-cable nudity, but plenty in taking on her first TV series.

The actress, who has appeared in movies including The Runaways and Mad Max: Fury Road (she played one of the wives) currently lives a quiet life with Ben Smith-Petersen, her stuntman husband of one year, in West Hollywood. But the Starz series could change that. “I’ve been dying for it to drop so people can start talking about it,” says Soderbergh.

Turn back the clock, and Keough had the kind of legacy upbringing that fascinates. Elvis Presley was her grandfather (though she never met him), and Michael Jackson was her stepfather for several years. So was Nicholas Cage. “I fast-forwarded some sex scenes” while watching GFE with mom, Lisa-Marie Presley, and dad, musician Danny Keough, she says. Keough spent part of her youth in Hawaii, craving work and finding odd jobs until she began modeling professionally at 14.

But the actress also is aware of her privilege. Soderbergh remembers casting her in a small role in 2012's Magic Mike. “She seemed very centered and calm and bright, and I made a mental note of, 'Keep an eye on her, remember her,' " he says.

Now fame — and the kind of paparazzi that pop up on grocery runs — looms.

“All I want is to work,” she says. “I don’t really care what comes along with it.”