She’s a smooth criminal. 

“Game of Thrones” star Sophie Turner plays a jewel thief in her new show, “Joan” — and it’s not all fiction. 

Based on Joan Hannington’s memoir, “I Am What I Am: The True Story of Britain’s Most Notorious Jewel Thief,” the show first premiered on ITV in the UK in September. In America, it premieres Oct 2 on The C.W (9 p.m.) and on Dec. 5 on BritBox. 

The show is set in 1980s London, and it’s a rags-to-riches story following Joan (Turner) a woman in her 20s who is the caring mother of a six-year-old daughter, Kelly (Mia Millichamp-Long), but she’s married to Gary (Nick Blood), a criminal. When he goes on the run, she takes the chance to make a new life for herself and her daughter by becoming a jewel thief. 

Known as “the Godmother” of the diamond heist, she notoriously stole uncut diamonds from a jewelry store where she was working, and swallowed them. 

Sophie Turner with Joan Hannington in an Instagram photo. Instagram / Joan Hannington

Sophie Turner plays a glamorous jewel thief in “Joan,” based on a true story. ITV

The real Joan Hannington from the ’80s. Instagram / Frank Dillane

“Best bank in the world, is your tummy. Best safety-deposit box invented,” Hannington wrote in her book.

Turner, 28, told Harper’s Bazaar that she initially related to Joan as a fellow mother, since she had recently given birth to Delphine, her second child with her ex-husband, Joe Jonas, 35. 

“I was incredibly hormonal at the time and really feeling that fierce protectiveness of the new mother,” she told the outlet. 

Turner married the musician in 2019 and welcomed daughters Willa, 3, and Delphine, 2 with him before finalizing their divorce in Sept. 2024 after a year-long battle. 

“Joan, at her core, is a mother who loves her child and will do anything for her,” said Turner. 

“Mistakes are made along the way, and it ends up being quite tragic for her, but she’s fighting for her child. I think any mother that watches this will be able to relate to it.”

Joan Hannington more recently, she’s now 67. Instagram / Joan Hannington

Sophie Turner in “Joan.” ITV

Joan Hannington in Spain in 1990. Instagram / Joan Hannington

She added that she also liked the fact that the show, “was a real story, and the most unbelievable one. It’s about resilience and ambition – this woman is so infectious, you can’t help but love her. I couldn’t give her up to anyone else!”

The real Joan Hannington did come visit the set, and she and Turner talked for hours.  

“I was shaking, terrified. And Joan walked in and burst into tears, and said: ‘You’re perfect, perfect.’” 

Hannington, now 67 and a grandmother, has been retired for 40 years, and lives a quiet small town life.

“She’s mad as a box of frogs, in the best way,” Turner described her. 

“She has this unbelievable energy – if she walked into a room of 300 of the top businessmen, women, entrepreneurs in the world, she would be the one telling them what to do with their lives. She’s so sure of herself, she’s so confident, she’s so funny, and she has the best laugh…”

Joan Hannington. Instagram / Joan Hannington

Joan Hannington in an undated photo. Instagram / Joan Hannington

According to Metro, in a Q & A panel about the show, Hannington said that she had never heard of Turner before, but she thinks, “they couldn’t have got anyone better.” 

“I’d never seen Sophie in anything, I’m in bed at seven o’clock every night of my life,” she went on. “I’m addicted to TikTok, so I don’t watch much telly, which was a good thing, because I didn’t have anything to compare her to.” 

In her book, “Joan,” Hannington wrote, “Swallowing diamonds was my life, my buzz, my drug. It was the only thing that I really liked doing. To me, I had a gift.”

Hannington was the youngest of six children born to a poor Irish family in London. When she was 13, she left home to get away from her violent father, former boxing promoter Richard O’Leary. She ended up marrying robber Ray Pavey and having her daughter, Debbie with him. (Her name was changed to Kelly in the show). After Debbie got put into foster care, Joan lied about her past to land a job at a high class jeweler in London. 

Sophie Turner, left, and Joan Hannington, right. Instagram / Joan Hannington

Joan Hannington on the set of “Joan.” Instagram / Joan Hannington

Sophie Turner as Joan and Mia Millichamp-Long as Kelly. ITV

“I was determined to get Debbie back but I needed money and a place to live,” she told The Sun. 

“One day, I was sent to the safe at the back of the shop, where the CCTV cameras didn’t operate, to ­collect some loose diamonds. I opened the safe and trays of brilliant white stones glittered back at me.My heart galloping, I realized the chance to make some instant money and regain custody of Debbie was ­staring me right straight in the face.”

She added, “I couldn’t believe my eyes. There were all these trays inside, and I’d never seen such big diamonds and emeralds — I just thought, ‘F–k it. I’ve got to have some of this I found the four trays they had sent me to get, and every one of them was full of loose stones.”

When she turned to carry out the stones, nobody was watching her.

“I was sweating like a pig…I grabbed a handful of diamonds off each tray and swallowed them,” she recalled. “I didn’t know it at the time, but I’d swallowed about £800,000 of stones.” 

After “nature had taken its course” hours later, she sterilized the gems in “a bowl of gin.” 

She didn’t get out scot-free, however, as swallowing jewels gave her ulcers, she claimed.  

Frank Dillane as Boisie and Sophie Turner as Joan Hannington in “Joan.” ITVX

Frank Dillane and Joan Hannington on the set of “Joan.” Instagram / Joan Hannington

After that job, she became lovers with Ronald Thomas Hannington, aka Benny Boisie (Frank Dillane in the show). He was an antiques dealer 17 years her senior, and a jewel thief. He taught her more about that way of life and credit fraud. 

According to the Manchester Evening News, Joan once told the Scottish Daily Record that Boisie had moved in with her “within weeks” of the two of them meeting and that “overnight” her council flat was “overflowing with priceless antiques.”

“Benny and I accumulated thousands of pounds a week in stolen gems, which we stashed at a bank in private deed boxes,” she claimed. “I had no idea of the total value of our cash and assets, but it must have run into millions.”

Joan Hannington and her son Benny attend the launch of ITV’s “Joan” Sept. 19, 2024. PA Images via Getty Images

Sophie Turner with Joan Hannington, and Frank Dillane. Instagram / Frank Dillane

Gershwyn Eustache Jr., Kirsty J. Curtis, Sophie Turner, Ruth Kenley-Letts, Anna Symon, Richard Laxton, Laura Aikman and Frank Dillane attend the launch of new ITV series Joan, at Jack Solomons Club in London on September 19, 2024. PA Images via Getty Images

In 1987, she had their son, Benny Jr., and began living more on the straight and narrow. 

Hannington never spent a significant time behind bars, and was only prosecuted twice. 

She was on probation for two years after stealing a car to visit her daughter, Debbie, and when she was 24, she was sentenced to 30 months in Holloway Prison for using a ­stolen check book.

Today, her son Benny is 37 and a rapper – and he even had a cameo in “Joan,” playing a bartender in the scene where his parents meet.

Turner told Harper’s Bazaar that she hopes this role “shows a completely different side” of what she can do.

“Because I think I’ve always played victims, and the one thing about Joan is she’s not a victim,” she said. “She’s had terrible circumstances in her life, but she is not a victim. She’s owned her life.”