It was a BIG deal. Samwell Tarly missed it (and also the deaths of his father and brother), but a major piece of the plot was just revealed on "Game of Thrones."

At the Citadel in "Eastwatch," Gilly read off Seven Kingdoms trivia while Sam tried to do his boring work and stewed over being blown off by the old maesters in his quest to help defeat the White Walkers.

Gilly asked Sam for the definition of "annulment." He answered that it's when a man sets aside his lawful wife. Gilly then reported that High Septon Maynard -- who recorded everything, including his own bowel movements -- "says here that he issued an annulment for Prince Rhaegar and re-married him to someone else at the same time in a secret ceremony in Dorne."

Rhaegar was married to (poor, innocent) Elia Martell. If that marriage was somehow annulled, and he got remarried, that "someone else" could only have been Lyanna Stark. And since Lyanna died just after giving birth to the guy we know as Jon Snow, that means Jon was the legitimate son of Lyanna and Rhaegar. It's a bit convenient to the plot -- and super inconvenient to poor Elia Martell, who got ditched by her husband, and saw her children murdered, then was raped and murdered herself by The Mountain.

#EliaDeservedBetter

Seriously, though, what were the grounds for annulment? Rhaegar and Elia had two kids together. Are fans just so happy for Jon to have a strong claim to the Iron Throne that they'll blow off this plot hole?

Jon seems close to learning the truth that he's a Targaryen. Bran Stark knows the truth, having seen his birth in a vision, and Drogon seemed to sense a fellow Targ. There's a lot of information flying around, between Bran's visions, the intel at the Citadel, and the record-keeping at Winterfell. It's only a matter of time before someone stumbles on the full story and shares it with BOTH known Targaryens. Plus, the recent HBO leak may have confirmed who is playing Rhaegar Targaryen on screen, possibly in another Bran vision, and since there are only two episodes left, he'll be coming pretty soon.

"Game of Thrones" Season 7 continues with Episode 6 on Sunday, Aug. 20 at 9 p.m. on HBO.

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