Getting Schooled: There's no good reason for cutting class (Room 222, 1972)

 From season 4 of Room 222:

An aspiring singer (guest star Chip Hand) is cutting class, at the expense of his grades. Pete Dixon (Lloyd Haynes) wants to know why. Charles Martin Smith also guest stars.

Toon fans know Chip better as the speaking & singing voice of Butch Cassidy a year later. Unfortunately, Chip passed away a number of years ago, a career cut short. I'm going to look up IMDB to see if he had any other primetime gigs.