Bobby Keys, a defining saxophonist of the rock era who offered a jolt both musically and personally to the Rolling Stones, died Tuesday. He was 70.

Keys, a hard-partying jazz lover born in Texas, befriended Buddy Holly as a teenager and gradually became a go-to saxophonist for rock acts including the Rolling Stones -- whom he first stumbled upon in 1964.

Keys provided the tenor sax that contributed to the blues sound of "Brown Sugar," one of the Stones' greatest hits, and toured with the rock legends for most of their five decades as a band.

"The Rolling Stones are devastated by the loss of their very dear friend and legendary saxophone player, Bobby Keys," the band said in a statement announcing his death.

"Bobby made a unique musical contribution to the band since the 1960s. He will be greatly missed," it said.

Keys was particularly close to guitarist Keith Richards, who was born on the exact same day -- December 18, 1943.

"I have lost the largest pal in the world and I can't express the sense of sadness I feel, although Bobby would tell me to cheer up," Richards said in a handwritten statement posted on Twitter.

"My condolences to all that knew him and his love of music," Richards said.

Besides the Rolling Stones, Keys also collaborated with the other giants of English rock, The Beatles. He joined John Lennon -- both in music and in drug use -- during the ex-Beatle's so-called "Lost Weekend" of estrangement from Yoko Ono.

Among other artists with whom he collaborated were Eric Clapton, Joe Cocker and Carly Simon. He also played saxophone on Marvin Gaye's "Let's Get It On."

Keys' rowdiness on the road was notable even by the standards of the Rolling Stones.

"I've been smoking pot for over 50 years, and I never let a day go by unless I'm in jail," Keys said in a 2012 interview with Rolling Stone magazine. "I am a devout pothead."

Richards, in his autobiography Life, remembered Keys' lifestyle when the Rolling Stones were staying at a villa in the southern French town of Nellcote, where the band recorded parts of the classic 1972 album Exile on Main Street.

Richards recalled that Keys one day "caused a disturbance by throwing his furniture out of the window in a moment of Texan self-expression."

Keys eventually retired from the road as his health failed. He died at his home in Franklin, Tennessee.