The former Doctor Who and The Crown star, 39, plays Daemon Targaryen in the story set 200 years before the events of the original sprawling HBO series, which became notorious for its explicit portrayal of sex and violence.
Emilia Clarke, who played queen Daenerys Targaryen, revealed after Game of Thrones had concluded its final series that she had felt uncomfortable with the “f*** ton” of nude scenes she was asked to do.
Speaking to Rolling Stone about the forthcoming prequel series, Smith said: “You do find yourself asking, ‘Do we need another sex scene?’ And they’re like, ‘Yeah, we do.’
“I guess you have to ask yourself, ‘What are you doing? Are you representing the books, or are you diluting the books to represent the time (we’re living in)?’
“And I actually think it’s your job to represent the books truthfully and honestly, as they were written.”
Asked about how many sex scenes he has, Smith jokingly added: “Yeah – slightly too much, if you ask me.”
The 10-episode series is based on George RR Martin’s Fire and Blood novel, which tells the story of House Targaryen.
Paddy Considine, Emma D’Arcy, Olivia Cooke, Steve Toussaint, Fabien Frankel, Sonoya Mizuno and Rhys Ifans will all also star.
Smith also reflected on the controversial ending of Game of Thrones, which divided viewers and prompted a petition calling for the finale to be re-shot.
He said: “I think you’re always going to disappoint some people. Ultimately, the body of work they produced stands up.
“Was it a perfect ending? It’s a matter of opinion. It didn’t bother me, I liked it.”
House of the Dragon is due for release on 22 August on Sky Atlantic and steaming service Now.
Additional reporting by Press Association