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Another evidence that Jon Snow (Kit Harington) will return to "Game of Thrones" season 6 may have just surfaced. There have been theories among fans that Jon is actually the son of Rhaegar Targaryen and Lyanna Stark (Ned's late sister) and was born in the Tower of Joy. Now, a filming location for the upcoming season may confirm it.

As fans have noticed, one of the newly announced filming locations, the Castillo de Zafra in Guadalajara, Spain, resembles the Tower of Joy from the books. In the books, the Tower of Joy was torn down long before the events of season 1. If the Castillo de Zafra indeed serves as a stand-in for the Tower of Joy, it will likely be featured in a flashback.

Adding fuel to the speculation, Watchers on the Wall recently reported that the show's casting an unnamed "legendary fighter" described as "a man in his thirties or forties who is a great swordsman and a paragon of knighthood. He carries a hugely famous sword on his back. The show is seeking a very impressive swordsman for the role- the best in Europe, for a week of filming fight scenes for a season 6 role. His ethnicity/race isn't specified, unlike many other roles."

The description reminds the book readers of Arthur Dayne a.k.a. the Sword of the Morning, who was a Kingsguard knight under the Mad King and one of Rhaegar Targaryen's closest friends. He was considered one of the greatest warriors in the Seven Kingdoms before he died at the Tower of Joy.

Should the show confirm fan theory about Jon's parents, it's believed that the show won't go this far and dig into the circumstances of his birth only to keep Jon dead. Thus, it is believed that Jon will have a presence in season 6 since he's the only major character alive who is related to an event in the Tower of Joy.

Filming for the sixth season of "Game of Thrones" is scheduled to begin this month for a 2016 premiere.