Legendary musician Isaac Hayes goes back to the '70s when he guest-stars on That '70s Show. Hayes begins shooting next week and his episode is scheduled to air in spring 2006 (exact date TBA). In this episode, Fez (Wilmer Valderrama) tries to create a hipper persona for himself at the beauty salon where he works as a shampoo boy. While at the salon, Fez has a fantasy in which Hayes shows up and performs a hilarious musical number.

That '70s Show airs Wednesdays (8:00-8:30 PM ET/PT) on FOX.

Hayes released his first solo album in 1967 and went on to become a renowned figure in mainstream, R&B and soul music. He has recorded over a dozen albums, including a record-setting seven No. 1 R&B albums. In 2002, Hayes was inducted into the Rock and Roll Hall of Fame, and he most recently released "Ultimate Isaac Hayes – Can You Dig It?", an anthology of his greatest hits. In addition to his musical career, Hayes has starred in numerous films, including "Shaft," "Dr. Dolittle 2" and "Reindeer Games." His television credits include a regular role as "Chef" on the animated series "South Park" and guest appearances on "The Hughleys" and "Veronica's Closet." Hayes also hosted the "NBA All Star Weekend."