"I'm a Time Lord from the planet Gallifrey,' said the Doctor, quite eager now to shock. 'It's in the constellation of Kasterborus, 29,000 light years from Earth. And as for my being an alien - well, to me you're an alien. Actually I'm quite used to humans, I lived on Earth for a while."
Sam studied him thoughtfully.
"Well, as aliens go you're an improvement on the little green guys with pointy heads."