Blues harmonica legend James Cotton, known for working with Muddy Waters and Howlin' Wolf, has died at the age of 81.

Cotton died Thursday of pneumonia while being treated at St. David's Medical Center in Austin, Texas, a rep for the musician announced.

Dubbed "Mr. Superharp," Cotton began his career as a teenager by touring with Howlin' Wolf and Muddy Waters, with whom he spent 12 years on the road.

Cotton was featured on Muddy Waters' 1960 album At Newport 1960.

In 1966, Cotton formed The James Cotton Band and collaborated with the likes of Janis Joplin, The Grateful Dead and Led Zepplin among others.

Cotton's accolades include a Best Traditional Blues Album Grammy for his 1996 album Deep In the Blues, a 2010 all-star tribute concert that took place at New York's Lincoln Center and the Festival International de Jazz de Montreal's 2015 B.B. King award.

The blues pioneer's latest album, 2013's Cotton Mouth Man, was also nominated for a Grammy.

Cotton is survived by his wife, Jacklyn Hairston Cotton, daughters Teresa Hampton and Marshall Ann Cotton, and son James Patrick along with his grandchildren and great-grandchildren.