The pair, who have been friends for nearly a decade, told their Instagram followers in a jokey video that they had moved in together.
Inevitably, the announcement caused much hilarity among their fandom, which has been desperate for some Outlander news since it was announced season six of the popular time-travelling series will air early next year.
Here is everything you need to know about Heughan and McTavish’s friendship.
When did Sam Heughan and Graham McTavish become friends?
The two actors didn’t know each other before they started filming Outlander back in 2013.
They met on-set and became close, mirroring the relationship of their on-screen characters.
Heughan stars as heartthrob Jamie Fraser in the Starz drama, who finds love with time-travelling World War II nurse Claire Randall, played by Caitriona Balfe.
Meanwhile, McTavish is Jamie’s maternal uncle, Dougal Mackenzie, who shares a strong bond with his nephew during the first four seasons of the show.
McTavish has previously told how the pair instantly hit it off when they first met, telling Stylist in an interview that Heughan “was really warm, charming and supportive”.
Off-screen, the hilarious pair’s friendship has continued to thrive.
They filmed their Scottish travel series, Men in Kilts, together in 2020, which seemed to cement their bond even further.
The docu-series sees the duo exploring their homeland together on an epic twelve-month road trip, learning about Scotland’s heritage, food, people and culture.
Do the Outlander stars live together?
The two actors announced that they had shacked up together in a joint Instagram Live video this week.
In the light-hearted clip, a rather tanned-looking Heughan and McTavish are seen sitting in a garden together with a glass of white wine in hand.
Heughan is the first to make a joke about their living situation, saying: “We do live together now, don’t we?”
McTavish quips, smiling: “We actually do. It’s very beautiful and we’re not ashamed to talk about it now.”
"It's the start of a beautiful relationship,” Heughan jests, before clinking his glass with McTavish.
While some fans speculated the actors could be staying with each other for work purposes, other social media users were quick to point out that they must be joking after one too many glasses of wine.
The video was actually made to tell fans about their new book, The Clanlands Almanac, which will explore their experience of Scotland and its culture while they filmed Men in Kilts.
It’s the follow-up to the duo’s first book, Clanlands, which the acting duo will be releasing as an audiobook.
Speaking about the new project, McTavish joked: “We are going to be trapped in some kind of sweaty box together for many many many hours.”
Is Sam Heughan married?
Heughan is happily married in Outlander, yet his fiery on-screen relationship doesn’t reflect real life.
He has previously opened up about being single, saying he would love to find a partnership like his one with Balfe in the drama.
Speaking to the Inquirer last year, he said: “The love that Jamie has for Claire - it would be amazing to find something like that myself.”
He is still believed to be single, but has previously been romantically linked to actresses MacKenzie Mauzy, Amy Shiels, Cody Kennedy and Abbie Salt.
Meanwhile, McTavish is married to his wife Gwen and has two daughters.
Not much is known about his relationship as the actor prefers to keep his personal life private.