From March 1967 — you know you’re hot when you’re featured in a Archie-Style comic book!  In this case, it’s “Tippy Teen”, and Leonard Nimoy is “Out of this World!”  The article is presciently predicts that ‘Len’ “will keep going strong for a long time”! And he does!  🙂   (I honestly don’t think anyone in real life calls him “Len”, but what a groovy guy!)