The Grammy Award-winning group will headline the fair's popular Evening of Music & Wine event on July 27 at the Paso Robles Event Center.
Led by Harry Wayne Casey, KC and the Sunshine Band soared to success in the 1970s with a string of funk-infused hits that included "That's the Way (I Like It)," "(Shake Shake Shake) Shake Your Booty" and "I'm Your Boogie Man."
The band previously played the fair in 2005.
KC and the Sunshine Band joins an entertainment lineup that includes pop star Demi Lovato, hip hop artist Pitbull, stand-up comedian Gabriel "Fluffy" Iglesias and blues rockers George Thorogood and ZZ Top.
Also slated to perform are several country stars, including Luke Bryan, Tim McGraw, Faith Hill and Dwight Yoakam.
Tickets for the Evening of Music and Wine concert cost $26 to $46, or $448 for a table of eight, and go on sale June 15. (Fans can purchase tickets via phone and online starting at 10 a.m. June 15, and in person at the fair box office, 2198 Riverside Ave. in Paso Robles, starting at 1 p.m.)