"You knew?" Xander asked.
"You knew!" Willow accused.
"I knew," the Doctor admitted. "But not only I." ...
"Yes."
"Did you?"
"Yes," said the Doctor. There was compassion in his face, but he volunteered nothing.
"It wouldn't be appropriate to tell Buffy," said Giles, "but can you tell me?"
"Are you certain?"
Giles exhaled sharply. "Yes."
The Doctor told him.
Giles looked at the Doctor a moment, then looked away a moment. "I'll be damned," he said in amazement. "I really did want to know."
"No you won't." The Doctor smiled and patted Giles' shoulder. "It's what makes you a good Watcher."