and I had to tell him The Truth. Aw. First bit of magic revealed. My baby's not a baby any more! (Well, he's seven, but YKWIM.)
Actually went better than I'd expected - having done all the havering about 'what do YOU think?' when I confessed he was OK. Said it was still magic but even more special now he knows Mummy and Daddy make all the special things happen. Bless him.
Still put his tooth under his pillow though - complete with letter he'd written to the Tooth Fairy earlier asking how old she is and what her name is. I asked whether he still wanted it and he said 'yes, I want to see what ideas you have'. 