In an interview with the Los Angeles Times, Matt Smith explained why he was more stressed out about Doctor Who than House of the Dragon.
He said: “The pressure that came with ‘Doctor Who’ is extraordinary [‘House of the Dragon’], you share it with like 10 other actors. Doctor Who is ‘Doctor Who’, Hamlet is ‘Hamlet’, you know?” Indeed, Doctor Who is unquestionably the protagonist of Doctor Who, while House of the Dragon has several characters sharing the spotlight , rather than focusing primarily on one person.
Smith added that he was only 26 when he was cast as Doctor Who – and he’s not sure he’ll “ever feel that kind of pressure again”. He told the LA Times: “There’s a huge focus on this job in the UK anyway. [‘House of the Dragon’] is a huge global franchise they tell me, but I just go to a studio in Watford to work and try to get the lines in the right order. I think anyone who leaves Doctor Who will miss Doctor Who forever because it doesn’t get any better. He is the most glorious character. Living with the idea of being able to time travel is incredible. It’s limitless. It’s a hard part to leave.”
Doctor Who is an incredibly popular series in the UK, where Smith lives. As such, he may have felt the show’s popularity more than the popularity of House of the Dragon, which has a more globalized fan base. He’s also older now than he was then, and he said that performing Doctor Who at that age helped him prepare for the intensity of House of the Dragon.