Erin Murphy's fraternal twin sister Diane Murphy is among the children at the birthday party (wearing a wig). She is credited as playing "Diane", but Samantha calls her "Annabelle". The twins shared the role of 'Tabitha' during Season 3 and, as they began to look less alike, Diane was dropped during season 4.
This episode was parodied on Married... with Children: Weenie Tot Lovers & Others Strangers/Bewitched: A Bunny for Tabitha (2002).
Both Carol Wayne (Bunny) and her younger sister Nina Wayne appeared in dim-witted roles in different episodes of the series. Nina was Beverly Wilson on Disappearing Samantha (1966).
Paul Lynde and Carol Wayne would later work together again on Love and the Nervous Executive/Love and the Hitchhiker/Love and the Great Catch (1970). In the 'executive' story, Ms. Wayne plays a very competent secretary who gets repeatedly fired due to the effect she had on her bosses.