"Oh, come on! You didn't really buy that, did you?" She looked at him incredulously. When she saw the confusion on his face, she doubled over in a fit of laughter. "You DID! Oh my God! You really did! I don't believe it!" She was incoherent now, she was laughing so hard. "Oh, Jack! I don't believe you! What I'd give to see him again for just one minute. Just to see the look on his face when he realized you'd believed him!"
"What do you mean? Come on. Let me in on the joke. Jack's not the Face of Boe?" The Doctor was confused, and just a little cross at being left out.
"No! Jack's not the Face of Boe you prawn!" She collapsed into another fit of giggles. "Please! Remember that time you left us in feudal Japan? We had hours to kill and we swapped stories. I told him all about the Face of Boe then. He made a dirty comment about how just a head was enough to be getting on with and I smacked him. Trust me, Doctor, he's NOT the Face of Boe! He must have filed that away to use against you later. He apparently had centuries to come up with it." She gave him a dirty look at that. She hadn't quite forgiven him for not telling her what had happened to Jack after the Gamestation.
"Well." He huffed. "He's lucky he's in another universe and I can't get to him. That's… that's just uncalled for. Here I've been all concerned about him living for millions of years and turning all giant-heady and here he's just been playing a practical joke. Hmmph. That's just… rude. That's what it is."
"Oh, please. You were gossiping about it to me like an old woman. You're just sore he pulled it off. If he had done it to anyone else, you'd be finding it just as funny as I am, you know."
"Well, I don't know about that," he sulked.
"No? How's this, then? You and I know he's not the Face of Boe, but the other universe-you doesn't, and probably never will. Whaddaya think about that?"
The corners of his mouth twitched for a second, then twitched again. "I think it's reprehensible. Absolutely, reprehensible." He was in full-on smirk mode now. "I feel very sorry for my other self. Just terrible for him in fact. Wish I could go and tell him myself to end the suffering." He turned to Rose and grinned. "You really are brilliant, you know that?"
"For what, figuring out that Jack isn't the Face of Boe or pushing you out of your sulk?"
"Oh, both, really. Or either. Doesn't matter. You're just brilliant."
"I know." She chucked her hip against his and gave him a wink. "Don't you forget it, though, yeah?"
"Not a chance!"