A flashback scene that takes place at the Tower of Joy has been confirmed in a new report on “Game of Thrones” Season 6. Preparations to film the relevant scenes in Spain are said to be underway, and the show may have a few celebrity cameos next year.

According to a report by LosSieteReinos, Castle Zafra in Spain will be used to depict the Tower of Joy in the next season. Filming at the location is expected to take place in late September, according to the report.

The report said that there was a casting call earlier that seemed to be for Arthur Dayne, a character from “A Song of Ice and Fire” book series, who was present during the major events that took place near the Tower of Joy. The scene is expected to be a flashback.

According to ongoing rumors, the scenes from inside the Tower of Joy may be filmed in HBO’s studio in Belfast. It is also expected that “Game of Thrones” Season 6 will show the scene that reveals what Ned Stark’s (Sean Bean) sister, Lyanna Stark, asked him to promise right before her death.

Another location in Spain, where filming is expected to begin soon, is Girona, the report said, adding that the location could be used to film scenes of Braavos. There is still no news about filming in other locations in Spain, and the report stated that it is unclear whether HBO will be filming in Croatia this time. The cast members reportedly went through their first costume fittings this week, and filming in Spain is likely to begin soon.

Meanwhile, according to a report by Vanity Fair, two celebrities may be making a cameo appearance in the next season. “It’s Always Sunny in Philadelphia” cast members, Charlie Day and Rob McElhenney, have reportedly been spotted near the set of the show.

The report added that executive producers David Benioff and D.B. Weiss had previously said that they were trying to find ways to allow celebrity cameos in “Game of Thrones” Season 6. There is no official confirmation about which celebrity cameos can be expected on the show next year.