Sophie Turner and Maisie Williams used to "try and kiss each other" during their Game of Thrones scenes.
The two stars became best friends on the HBO fantasy drama - which came to an end last month - where they played sisters Sansa and Arya Stark respectively, and now Sophie has revealed the duo used to play tricks on the crew by trying to lock lips in the middle of their scenes.
Sophie, 23, said: "We fully knew [that people thought we were together]. We played into it. We did. So on the set, we would kind of do the scene then try and kiss each other in the middle of the scene and see if anyone would react."
But the pretend smooches didn't get the reaction they were hoping for, as relationships between on-screen family members were common on the show, with siblings Jaime and Cersei Lannister having children together, and Jon Snow having a romance with his aunt Daenerys Targaryen.
Sophie added to Conan: "It's Game of Thrones, so incest is so normal that they were like, 'All right, that's fine.' It was probably the most tame thing that happened on the show, actually."
The blonde beauty also insisted the kisses were just jokes to make people believe she and the 22-year-old star were dating.
She said: "Yeah, you know, sometimes you just wanna make out with your best friend."
Meanwhile, Maisie recently said she was destined to be friends with Sophie, and described Game of Thrones as "one big convoluted way" to get the two pals to meet.
She said: "Of course, although the show is ending for us as a group of friends it's just the beginning.
"Sophie and I say we can't wait for the rest of our lives - it's like we got married! It's one big convoluted way for me and Sophie to meet each other."