James Earl Jones was the first celebrity guest to appear on Sesame Street, appearing in segments in which he recited the alphabet and the numbers one through ten for the show’s pilot in 1969. According to The Muppet Wiki, Jones studied acting under Sesame Street actor Will Lee who played Mr. Hooper, and Jones’ alphabet and number clips were later edited into episodes during the show’s first season. The alphabet segment is included on the Sesame Street: Old School – Volume One (1969-1974) DVD.
The official Sesame Street Twitter account recently shared the video of Jones reciting the alphabet to celebrate the show’s 45th anniversary.
— Sesame Street (@sesamestreet) November 10, 2014
via Sesame Street