A source confirmed to online news portal, people.com that they are officially a couple now.
The actors first stirred up relationship rumors in 2012, in sync with their fictional "Game of Thrones" counterparts, .
Though they reportedly split after a year, they later reconciled and continued to fuel romance speculation until they officially confirmed the relationship in April 2016, making their red carpet debut as a couple at the Olivier Awards in here.
The pair also took out a wedding announcement in their hometown newspaper of the Times in England, that read, "MR. K.C. HARINGTON AND MISS R.E. LESLIE. The engagement is announced between Kit, younger son of David and Deborah Harington of Worcestershire, and Rose, middle daughters of Sebastian and Candy Leslie of Aberdeenshire."
A month after going public with the relationship, Harington, 30, opened up about the early days of the romance, which began on set while shooting in Iceland for season 2 - admitting that those weeks were his favourite of the series, and for good reason.
Back in 2014, Leslie, 30, also touched on her relationship with her costar - and their famous season 3 intimate scene.