Sophie Turner had a "vile" experience kissing co-star Kit Harington for their upcoming horror film, "The Dreadful."Turner and Harington starred alongside each other in "Game of Thrones" as brother and sister from 2011 until 2019. After portraying siblings Sansa Stark and Jon Snow, their bond transcended TV and the duo found themselves just as close in real life.After Turner suggested Harington for the lead role in "The Dreadful," he pointed out filming might be a little awkward.SOPHIE TURNER SLAMS PARENTING POLICE AFTER BEING CRITICIZED FOR ATTENDING OASIS CONCERT WITHOUT HER KIDS"So, I sent the script to Kit, and he kind of sent me a message back going like, Yeah, Id love to, but this is going to be really f------ weird, Soph," Turner said on "Late Night with Seth Meyers.""And I was like, What is he talking about? Then I wasreading[the script] and its like, Kiss, kiss, sex, kiss, sex And then Im like, Oh, shoot, thats my brother."LIKE WHAT YOURE READING? CLICK HERE FOR MORE ENTERTAINMENT NEWSAfter much consideration, Turner and Harington decided they "kind of had to do it" because they couldn't turn down the script."We put it out of our minds, and then we get on set, and its the first kissing scene, and we are both retching," she recalled. "Like, really, it is vile. It was the worst."CLICK HERE TO SIGN UP FOR THE ENTERTAINMENT NEWSLETTERTurner began filming "Game of Thrones" at the age of 12. By the time the HBO series wrapped, the TV star was 23.The Emmy-nominated actress described filming alongside Harington, Emilia Clarke, Peter Dinklage and more as the "best acting class.""I never had proper formal training, so I got to learn from the amazing actors around me, which I felt like I won a competition," Turner said on the "Dish" podcast. "But it was great. We all were a family.""My character, I got to live with," she added. "So it felt like we kind of merged into one person by the end of it. But it was amazing."