My personal opinion is that Jack is the Face of Boe — it was implied that he was and so I think it is true.
Is Jack the Face of Boe? If you, in my opinion, choose to be pedantic and not accept Jack for his stated true identity then have that judgement, but I think he is Boe because it just seems so very likely. February 11, 2013.
As for the whole couldn't die thing? Then in the episode New Earth , The Doctor: Well even the TARDIS needs to fuel up at the rift, who's to say it just didn't take 5 billion years for his life force to run out.
Now that would be impossible. This isn't an in-universe confirmation of anything other than Jack's sense of humor and his knowledge that "The Face of Boe" exists and he's making a joke.
Jack was born on the Boeshane peninsula, and as a child model he was nicknamed the face of Boe. And what about me?
They even showed an image of the Face of Boe on the screens. Can you fix that? Jack says he was once known as the Face of Boe.
Other references made to it. February 11, 2013 Tweet.
Is there anything beyond subtle hints that Jack becomes the Face of Boe? That's a relatively short time, evolutionarily speaking, for Jack to have evolved into the Face of Boe. However, not even the Doctor knew whether Jack could die of old age, so I am wondering: What Happened to the Kovarian Chapter?
Will I ever be able to die?