And according to the Daily Mail, the co-stars (who are known to have a bit of a laugh) decided to have some fun with their wedding invites, using a photo of Harington as Jon Snow for the postal stamp.
"The 200 guests invited to see the 31-year-old actor marry his former Game Of Thrones co-star Rose Leslie at a Scottish castle were tickled to see the envelopes were adorned with a stamp featuring Kit as Jon Snow," the site reads.
The stamps - pictured below - were released as part of a limited edition run earlier this year and are still available, if you happen to be in the UK anytime soon (Daenerys for us, please).
"They organised the wedding quickly because they didn’t want information to leak," a source told Daily Mail.
"But putting Kit's face on the envelope might be a bit of a giveaway, at least for postmen across the country."
So if you see a Jon Snow stamp in your letterbox, get excited.