A letter once a year To let you know whether I've been good And all the kids at school Said you're not real, but I knew the truth Nobody, nobody, nobody else Only Santa knows When you're asleep Only Santa knows What cookies you leave Only Santa knows If you really do believe Only Santa knows I saw you cross the moon I ran inside to go straight to bed In the magic of the night I close my eyes and watch reindeers fly Nobody, nobody, nobody else Only Santa knows When you're asleep Only Santa knows What cookies you leave Only Santa knows If you really do believe Only Santa knows I can't wait 'til Christmas morning Before the day's begun I'll check the garden to see if all of the carrots are gone Tell mom and dad that we've got presents Underneath the tree We'll have to wait and see 'Cause only Santa knows When you're asleep Only Santa knows What cookies you leave Only Santa knows If you really do believe Only Santa knows Only Santa knows Only Santa knows ♪ (He's on the roof)