Harington's rep confirmed to ET that the couple has welcomed a baby boy. The confirmation comes after Harington and Leslie were spotted holding hands on Tuesday in London, with Leslie holding their newborn baby, in pictures published by Page Six.
Harington's rep tells ET, "Yes we can confirm they have had a baby boy and are very very happy!"
In October, 34-year-old Leslie talked about her excitement at welcoming their first child together.
"I am thrilled to be expecting, and I can't wait to meet the new member of our family!" she told The New York Post.
In an interview with GQ Australia last January, 34-year-old Harington talked about potentially having children with Leslie -- and how amazing it is that they would get to see a part of their parents' love story onscreen.
"It dawned on me, recently," Harington said. "And I have no idea if we will, but say me and Rose do have children. They'll know. They'll be able to see the genesis of their parents getting together. Which is quite a wonderful thought, really."
"I thank the show for everything," he continued. "But more than anything else, I thank it for introducing me to her."
Watch the video below for more on Harington and Leslie's love story.