Lopez died less than a week after his 76th birthday
Buena Vista Social Club founding member Orlando "Cachaito" Lopez has died in Cuba aged 76.
The double bass player died in a Havana hospital from complications after having prostate surgery.
Lopez became a worldwide sensation as part of the group of elderly musicians who were living quietly in Cuba before being brought together in 1996.
He was considered to be Buena Vista's "heartbeat" in the band's mix of traditional Cuban rhythms.
"It is a great loss for the group and for Cuban music because he was a superb bassist and a brilliant band mate," said Manuel "Guajiro" Mirabal, the group's trumpeter.
"He was an excellent person and the quality of his music was, honestly, unparalleled."
Manuel Galban, a Cuban musician who played with Lopez for decades, said he had lost "a great companion".
"I will remember him as marvellous, both in his music and as a person," he told the Associated Press.
Family members plan to cremate the body but there was no immediate word on funeral services.
The Buena Vista Social Club, which was brought together by American guitarist and producer Ry Cooder, has lost many of its key members of late.
Singer Compay Segundo, pianist Ruben Gonzalez, and vocalists Ibrahim Ferrer and Pio Leyva have all died in recent years.
But Lopez was also a star in his own right independent of Buena Vista, with his debut album Cachaito winning a BBC Radio 3 Award for World Music in 2002.
Born in Havana in 1933, Lopez hailed from a family of at least 30 bass players, including his uncle, legendary bassist Israel "Cachao" Lopez.
Lopez originally played the violin, but eventually took up the bass after his grandfather urged him to follow in the family's musical footsteps.
But he only gained international fame after joining the Buena Vista Social Club.
German film-maker Wim Wenders released a documentary titled Buena Vista Social Club, in which he profiled the musicians whose talents had all but been forgotten. It was nominated for an Oscar in 2000.