Fans have long been wanting to believe a theory that a popular “Game of Thrones” character is a secret Targaryen. While they still likely don’t have a chance of seeing it unfold when the show airs its final season in 2019, an Instagram post by one of the show’s stars could reignite the spark of this particular theory once again.

The theory, which claims that Tyrion Lannister (Peter Dinklage) is secretly a Targaryen and now Tywin Lannister’s (Charles Dance) son, is one that fans have tried to prove for a while, based on the character’s description in George R.R. Martin’s “A Song of Ice and Fire” book series. On the show, however, there doesn’t appear to have been any concrete proof the theory is true, save for Tywin’s final line to his son before he murdered him in Season 4, and the fact that Tyrion was able to touch Daenerys’ (Emilia Clarke) dragons without repercussions.

However, a recent Instagram post by Lena Headey, who portrays Tyrion’s sister, Cersei, on the show, has led to some trying to stretch the theory once again, highlighting the caption she used on the image as a means of proving she was hinting the theory was true.

Game of Thrones A theory about Tyrion Lannister (Peter Dinklage) will likely gain new traction.  Photo: Macall B. Polay/HBO

“Now this is more like it. Congratulations to my brothers (literally) from other mothers. I’m a lucky lucky sista to these Mistas,” she captioned the photo, which featured Dinklage, Nikolaj Coster-Waldau and herself in costume and making funny faces.

Though the post was made to congratulate Dinklage and Coster-Waldau on their Emmy nominations for the show, Digital Spy admitted that they believed it was easy to try and examine the caption and prove it was alluding to the long unproven fan theory.

Of course, this isn’t the first thing that isn’t directly correlated to the show or on-set storylines that has been linked to the theory. After Dinklage was featured in a Super Bowl commercial for Doritos, where he was seen breathing fire, he was forced to quickly shut down theories that it was a hint Tyrion was a Targaryen.

This isn’t the first recent post regarding a member of the cast where fans thought it might be a spoiler for the final season. Sophie Turner, who portrays Sansa Stark on the series, was forced to shut down rumors that a tattoo she had inked on her arm after she wrapped the series was a spoiler about what happens.