In Season 6, Game of Thrones made some major reveals about Jon Snow's lineage, answering questions that fans have had since the very first season. Though it had been assumed for years that Jon wasn't actually Ned's bastard son, as he'd always been led to believe, there was no confirmation until the key flashback to his birth in Season 6. That was when it was revealed that Jon was actually the secret child of Ned's sister Lyanna and Rhaegar Targaryen, Daenerys' older brother. Viewers got to see Lyanna for the first time in the flashback, but will they ever get to see Jon's biological father? Will Rhaegar Targaryen be in Game of Thrones Season 7?
There definitely seems to be a chance that the late prince will be making an appearance, presumably in another flashback. Though there's been no confirmation, rumors are flying that a musician named Devin Oliver has been cast as Rhaegar thanks to some hints Oliver has been dropping on his social media accounts. Oliver is the lead singer of the electronicore band I See Stars, which actually suits Rhaegar, who has been described in both the books and show as a lover of music. Oliver also has that signature Targaryen look down pat.
Oliver posted a photo of himself to Instagram (see above) back in September with a very telling caption: "I may or may not have made an appearance in Game of Thrones Season 7," alongside a monkey emoji with its hands over its mouth. Obviously the monkey emoji is the most revealing detail here. There are certainly numerous characters Oliver could be playing ("making an appearance" could literally mean anything from background work to saying a single line), but the plot thickened with a comment he made on Twitter shortly after.
When Sam Haysom, the Senior U.K. Culture reporter at Mashable, tweeted about the rumors of Oliver playing Rhaegar specifically, Oliver responded that his lips were sealed (i.e. the old-fashioned way of using the monkey emoji). If Rhaegar does make an appearance on the show in Season 7 (played by Oliver or not), then it looks like the show might be delving deeper into its own history. That can be very useful in explaining just how Westeros reached its current disastrous state, as well as uncovering some of the deeper secrets that have plagued its residents for years.
There might not be any guarantee that Oliver is playing Rhaegar (or that Rhaegar will even be showing up in Season 7), but this theory definitely seems more than a little plausible. And I am so here for it.