S. D. (Special Delivery) Kluger is the narrator of the Rankin/Bass special Santa Claus is Comin' to Town. S.D. is a friendly mailman who drives a snowplow, and tells the local children how Santa Claus came to be.
S.D. later served a similar function in a non-Christmas Rankin/Bass special The Easter Bunny is Coming to Town.
The character is a caricature of his performer, Fred Astaire.