With production already under way on Game of Thrones Season 7, there has been no shortage of rumors swirling regarding new cast members. We reported last month that Jim Broadbent has come aboard as the first new cast member for Season 7, and earlier this month, a rumor was shot down that Angela Lansbury had joined the cast. Today anorher rumor has surfaced, which indicates a major role has been cast. If you haven't caught up with Game of Thrones Season 6 yet, there will be SPOILERS below, so read on at your own risk.

After years of speculation, the long-held fan theory "R+L=J" was essentially confirmed in the Season 6 finale. Bran Stark's (Isaac Hempstead Wright) greensight flashback showed that Ned Stark's sister Lyanna gave birth to Jon Snow in the Tower of Joy, and while it wasn't explicitly said who the father was, it is believed to be Rhaegar Targaryen, the older brother of Daenerys Targaryen (Emilia Clarke). Fans had been lead to believed that Jon Snow was Ned Stark's bastard, although fans formulated the R+L=J theory since it seemed so out of character for Ned, one of the most honorable men in Westeros, to have fathered a bastard. HBO released an infographic this summer that confirms Rhaegar and Lyanna are Jon's parents, and now it seems we may finally get to see Rhaegar in Season 7, if a new rumor is proven to be true.

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Devin Oliver, singer for the American band I See Stars, recently posted a very interesting photo on Instagram. The blonde-haired singer teased in the photo's caption that he, "may or may not have made an appearance in Game of Thrones Season 7," which immediately lead fans to speculate that he may be playing Rhaegar Targaryen. Mashable reached out to HBO for comment on this rumor, but the network said they don't comment on casting speculation.

As you can see in the photos below, the singer, who has no acting credits to his name, bears quite a striking resemblance not only to Daenerys Targaryen, but her late brother Viserys (Harry Lloyd), who was brutally killed by Khal Drogo (Jason Momoa in the first season. After the rumor surfaced, a well-read Redditor pointed out that, in George R.R. Martin's books, Rhaegar sung a song at Harrenhall that brought tears to Lyanna's eyes. It's possible that, if Devin Oliver has been cast as Rhaegar, his singing skills will be put to use.

It's worth noting that, in the 10 months between Season 5 and Season 6, HBO didn't confirm any cast members whatsoever, so we likely won't get any confirmation on this report until Season 7 debuts next summer. The hit fantasy series based on George R.R. Martin's novels recently started filming Season 7, a few months later than usual, since the arrival of winter in Westeros requires a colder climate for the production. Take a look at Devin Oliver's Instagram photos below, as we continue the long wait for Game of Thrones Season 7.