Music is a main feature of the program; the show is a significant outlet for American folk music of many genres, especially country, bluegrass, blues, and gospel, but it also has guest performers from a wide variety of other styles of music, including classical, opera, and music from a number of different countries. The country musician and former record company executive Chet Atkins appeared on the show many times, as did singer-songwriters Mark Knopfler (lead guitarist and frontman of the bands Dire Straits and the Notting Hillbillies) and Jeff Lang. Folk/gospel duo Robin and Linda Williams had been regular guests since 1976, and often join Keillor and another female performer, often Jearlyn Steele, to form "The Hopeful Gospel Quartet". Peter Ostroushko, Greg Brown, Jean Redpath, and Prudence Johnson, among others, were recurring guests on the program between 1974 and 1987. The Wailin' Jennys and Andra Suchy were also recurring guests, and when the show travelled, Keillor generally featured local musicians and acts.