Ozzy Osbourne's tour manager, Robert "Bobby" Thomson, died Thursday apparently from throat cancer.

The 50-year-old Scotland native, who occasionally appeared on "The Osbournes," was found dead in his bed at the Townsend Hotel in the Detroit suburb of Birmingham, Michigan. Ozzfest began a two-night stint that night at the DTE Energy Music Theatre in nearby Clarkston.

"We are devastated by the loss of our dear friend Bobby," Ozzy said in a statement. "He has been a part of our family for 23 years and loved very much. He will be greatly missed by all of us. Our sincerest sympathies go out to the Thomson family."

Thomson, who battled throat cancer for 18 months, was found at 4:30 p.m. after apparently dying in his sleep, according to a spokesperson for the Osbourne family. An initial examination showed no sign of foul play.

The tour manager had lived in the Los Angeles area for several years with his wife and two sons, ages 19 and 10.