Notorious secret-keeper Kit Harington finally had some information withheld from him.

Harington had no idea that his Game of Thrones character, Jon Snow, would be reuniting with his long-lost sister Sansa (Sophie Turner) in last Sunday's episode, director Dan Sackheim tells TVGuide.com.

"They do many, many drafts of the scripts before they give them to the actors. And directors, by virtue of the fact that they have to be there prepping, have access to the scripts many times well before the actors have seen it," Sackheim, who helmed "Book of the Stranger," tells TVGuide.com. "Just like everyone had to keep the secret of whether Jon Snow was alive or not, you're requested not to talk about the material in front of the actors until they see the script."

That means that after months of Harington having to keep Jon's return a secret from the entire world, the tables turned on the actor. "I was with Kit in many sittings when he was talking about how much he hoped he'd get a chance to play a scene with Sophie Turner. So I was privy to the information that [Harington and Turner] weren't for a while," Sackheim recalls.

Kit Harington and Sophie Turner,<em> Game of Thrones</em>Kit Harington and Sophie Turner, Game of Thrones

When the actors finally got the script for "Book of the Stranger," they were thrilled to see Sansa and Jon reuniting - and to share their first scene together in the show's history. "[They] talked about it all the time," Sackheim says, "the sort of weirdness of it and the joy of finally coming together."

When Sansa and Jon see each other for the first time at Castle Black, they initially seem paralyzed by the sight of one another. But once the shock fades, Sansa and Jon run towards each other into an emotional embrace that could melt a White Walker's heart. Without saying anything, the scene says so much about the Stark siblings' relationship and everything they've been put through since leaving Winterfell in Season 1, which is exactly what Sackheim wanted.

"At the end of the day, you handle any scene like, 'What's the truth?' And in that case, the truth was these two people are coming together that love each other but have been estranged, and you try to find some active things for people to play. And in this case, it was disbelief and fear," Sackheim says. "Disbelief that it's really her and him, and fear that it may not be true. So that's why the approached each other sort of cautiously."

What did you think of the Stark reunion?