Game of Thrones
A popular fan theory about Daario Naharis (Michiel Huisman) appears to have been debunked by a recent "Game of Thrones" casting announcement. HBO

Fans have several theories about what may or may not happen on the final season of "Game of Thrones," but some of the more popular guesses at what will unfold during Season 8 have already been debunked, including one that many believed would bring Daario Naharis back to the show.

According to Watchers on the Wall, actor Marc Rissman has joined the HBO series' cast for the final season, and will bring the role of Harry Strickland to life onscreen. While the name is unfamiliar to those who aren't familiar with George R.R. Martin's books, those who have read the novels the series is based on will recognize him as leader of the Golden Company, a mercenary group in Essos.

Fans who watched the Season 7 finale will recall that Cersei (Lena Headey) had sent Euron (Pilou Asbæk) to Essos to secure the Golden Company to help her in her fight to remain on the Iron Throne. Noting that when she set off for Westeros at the end of Season 6, Daenerys (Emilia Clarke) left her lover, Daario Naharis (Michiel Huisman) behind, fans believed that making him the new leader of the Golden Company would be the perfect way to reintroduce him into the show's plot in the final season, and would pit him as having to choose between the woman who is paying for his services, and the one whom he previously worked for and grew to love.

However, the introduction of Harry Strickland to the storyline seems to thoroughly toss that theory out, though Digital Spy notes it isn't necessarily a sign that Daario won't come back with the Golden Company. In that case, it would make sense that he would be arriving in Westeros with the Golden Company to fight against Dany, because while a member of the group, he wouldn't have enough power in his position to refuse the job.

While that theory has been officially debunked however, others seem to only be growing stronger as the new season approaches. Though no one from HBO will confirm whether or not the theory over how Cersei will die (the show has not confirmed if she will), a former series actor has come forward to venture that fans will not only see the Queen of the Seven Kingdoms die, but that it will be at the hands of her brother and now former lover, Jaime (Nikolaj Coster-Waldau).

Tom Hopper, who took over the role of the ill-fated Dickon Tarly in Season 7, revealed he believed the theory that Jaime would kill his sister was going to be how the series came to an end.

"I think Jaime is probably going to end up killing Cersei," he said.

The theory is one that has been swarming amongst fans for a long while, ever since the Season 5 premiere of the show, which saw young Cersei receive a prophecy for her future from Maggy the Frog (Jodhi May).

On the series, fans saw Cersei learn that she wouldn't marry the Prince, but the King, which she did after Robert Baratheon's (Mark Addy) successful rebellion. The prophecy also stated that she would have three children and he would have 20, and all three of hers would die, with the dire warning "gold their crowns and gold their shrouds."

While that part of the prophecy has all proven to be true, there was another part which has yet to feature on the show, but did appear in the books. There, the theory continued that one day a "Valonqar," or High Valyrian for "little brother," would eventually choke her to death. The most literal interpretation of that part of the prophecy would mean that either Cersei's little brother Tyrion (Peter Dinklage) would do it, or Jaime, who while her twin, is still younger than her.

"Game of Thrones" is expected to return in 2019.