Glen Campbell

Glen Campbell

Glen Campbell — legendary country music singer best known for his 1975 hit, “Rhinestone Cowboy” — has died after a long battle with Alzheimer’s … TMZ has learned.

Campbell died Tuesday around 10 AM in a Nashville facility for Alzheimer’s patients … according to a source close to his family.

The musician released more than 70 albums over a 50-year career, and had a series of hits in the ’60s and ’70s including “Gentle on My Mind,” “Wichita Lineman,” “Galveston,”…