The globe-trotting show House of the Dragon is set well over 100 years before the Game of Thrones. The situation makes cameo appearances by the original cast members quite unlikely but not impossible. Since it is a fantasy show, there still are ways around the plot question of how someone could show their face when they won’t be born for another century.
Taking an example, there exists one character who wasn’t just born by the period of House of the Dragon but is getting on in years: Melisandre, known as the Red Woman, is around 400 years old by the period of Game of Thrones, having elongated her life using the power belonging to the Lord of Light. She could already be over 100 years old at the time of House of the Dragon’s happening, which means she would already be aware of her fair share of magic.
Would actor Carice consider appearing in her role on the GOT prequel show? “Would I [return]? If the storyline was good – yes, why not?” she told Digital Spy. “But I think it would be more fun to show the character as a young one or a child – to dig deep down into her slave routes because it could then go forever like that.”
But there is an exciting storyline there, and I think it might become a bit boring to later drag me out again. It’s better to have another actor do it. But, you know, I could never say no.