Turner, 20, and Williams, 19, who play sisters Sansa and Arya Stark on the HBO series, showed off their matching ink in sleeveless dresses at the 2016 Primetime Emmy Awards on Sunday.
"We got matching tattoos!" Turner told E! News on the red carpet. "I got it in peach because my mum was like, 'Make sure it doesn't show up!'"
"We were always planning from Season 1, if we make it all the way through, hopefully we can all get a matching wolf or something. But we don't know if we're going to make it, so Maisie and I were like, 'Okay, let's get these ones before anyone kills us,'" she revealed.
Turner and Williams got "07.08.09" tattooed on their forearms to commemorate the date they landed the roles of Sansa and Arya. The co-stars will reprise the characters on Game of Thrones Season 7 in 2017.
"I was actually speechless [when I got the scripts]," Turner told E!. "This season is unbelievable and I think fans are going to be really satisfied. It's crazy."
"I can't even describe this season," she added to TV Line. "It's the best season yet. It's going to be insane. It's gonna be better than last season. When I read the scripts I nearly fell off my chair, I couldn't believe it. Jaw dropped."