Trivia / Star Trek: The Animated Series S1 E2 "Yesteryear"

• Approval of God: Gene Roddenberry considered this the only canon episode of the series.
• Children Voicing Children: Nine-year-old Billy Simpson voices Young Spock.
• One-Take Wonder: Billy Simpson recorded his lines for what he had believed to be an audition for the character of Young Spock, only to be informed once he got the part that they would be used in the completed episode. As a result a number of the lines (which were read in isolation, without context from the rest of the script) have a very "cold reading" quality to them, particularly the line "I will bring a healer here", where emphasis is placed on the wrong word ("healer" instead of "here"). It winds up appropriate for a Vulcan child.
• Role Reprise: Mark Lenard as Sarek, one of just three guest actors from TOS to reprise their role. Jane Wyatt notably does not return as Amanda (though her likeness was used), with Majel Barrett voicing her instead.