The Doctor grinned. "Well, you see, the Captain Jack Harkness I know - and I happen to know him rather well - looks nothing like you and was born in the 51st century. I also picked him up in 1941, which is why this is a bit confusing, but I can only assume that he was pretending to be you at the time."
He turned to Toshiko. "Torchwood? Really? You work for Torchwood?"