No information about his condition or location was released.
The 89-year-old musician was diagnosed with Type II diabetes more than 20 years ago. Born Riley B. King, he began his recording career in the 1940s and has released more than 50 albums, according to his website. King's hits include "Three O'Clock Blues," "The Thrill Is Gone" and "When Love Comes to Town," a collaboration with U2.
King was inducted into the Rock and Roll Hall of Fame in 1987.
Last October, King fell ill during a show and was diagnosed with dehydration and exhaustion, and canceled the rest of his tour.