"Game of Thrones" is currently filming its sixth season in various parts of the world, and fans of the HBO series have been keeping tabs on production through social media reports. Recently, Watchers on the Wall reported that according to Los Siete, Rienos, Clive Russell, who plays Brynden Tully on the show, was seen filming in Northern Ireland last week.

Tully, also known as The Blackfish, is Catelyn Stark's uncle, and the character has not been seen since season 3. With Russell's return to the show, many are speculating that an important storyline from the "A Song of Ice and Fire" series will be played out in season 6, which involves The Blackfish defending Riverrun from a siege, led by Jaime Lannister (Nikolaj Coster-Waldau).

In "A Feast of Crows," which is the fourth book of George R. R. Martin's novels, the Siege of Riverrun was a big storyline, and many thought that this wouldn't be featured on the show as "Game of Thrones" slightly deviated from the books in the fifth season. It can be recalled that instead of storming Riverrun, Jaime went to Dorne to get Myrcella, and up until Russell's sighting in Ireland, it was unknown whether his character was dead or alive after the events of season 3.

Meanwhile, Watchers on the Wall reports that Coster-Waldau and Jerome Flynn, who plays Bronn in the series, were also spotted filming in Northern Ireland. The website reports that an assault scene was filmed in the area and that fans should expect to see Jaime and The Blackfish having an argument.

The website was also provided by a fan with pictures of the Riverrun set, and the photos reveal that a wooden structure has been taking shape on the set, along with a drawbridge. The photos were taken on Tuesday, Oct. 6.

"Game of Thrones" is expected to return on April 2016.