Russell T. Davies har sagt att sammanslagningen av Face of Boes story med Jack Harkness historia hände efter att båda tecknen hade introducerats. Det finns tillräckligt med likhet för att det är trovärdigt, men Harkness är en sådan trickster att det kan vara ett stort skämt.
There was that moment where you revealed that Jack would eventually live so long that he'd become the Face of Boe. Was this something you planned all along with the character?
It wasn't exactly planned. I did spend a long time thinking about Jack's immortality, and one day it occured to me there was another immortal character on the show. It made me laugh. To be honest, on the screen, it's couched in terms that are not absolute gospel. There are these spin-off books and comic books, and every now and then I'll see a script for one where they say definitively that he's the Face of Boe, and I always stop those from being printed. I have my own personal theories, but the moment it became very true or very false, the joke dies.