Glen Campbell, the grinning, high-pitched entertainer who had such hits as Rhinestone Cowboy, Wichita Lineman and Galveston and spanned country, pop, television and movies, has died. He was 81.

Campbell's publicist Sandy Brokaw says the singer died Tuesday morning in Nashville. No cause was immediately given. Campbell announced in June 2011 that he had been diagnosed with Alzheimer's disease and that it was in its early stages at that time.

Campbell was one of the biggest stars of the late 1960s and 1970s. He sold more than 45 million records, had 12 gold albums and 75 chart hits.

He co-starred with John Wayne in the 1969 movie True Grit and had a weekly audience of some 50 million people for the Glen Campbell Goodtime Hour on American television from 1969 to 1972.

Campbell released his final album Adios in June.