The Spanish singer died in Sant Pau hospital in the city of Barcelona, staff there said, without giving further details.
Spanish media said that Caballe entered the hospital last month because of a gall bladder problem. However, Caballe's family requested the exact cause of death not be released, hospital spokesman Abraham del Moral told AP.
A government source said Sanchez would attend Caballe's funeral, which will be held in Les Corts morgue, in Barcelona, at midday on Monday. A great ambassador of our country dies, an opera soprano recognized internationally.
Barcelona's Liceo opera house, where Caballe performed over 200 times, and Venice's Teatro La Fenice also published tweets lamenting her loss.
Caballe was born in Barcelona, and began her professional career in Basel in 1956, as Mimi in La Bohème.
Manchester United Will Not Sack Jose Mourinho Before Their Season Ends
On Saturday, the Red Devils host Newcastle United , with both sides looking to create a bit of momentum. Jose Mourinho is unable to control his squad with some players wanting him to be sacked immediately.
Caballe starred in 90 opera roles with almost 4,000 performances.
Her first global hit was in NY at Carnegie Hall, with her portrayal of Lucrezia Borgia of Donizati replacing the main mezzo-soprano Marilyn Home.
She first made a global splash when "Barcelona", her song with Queen singer Freddie Mercury, became the anthem for the 1992 Olympic Games. She was particularly admired for her purity of voice, vocal shadings and exquisite pianissimos.
She was ordered to pay €254,000 (£223,304) and accepted a six-month suspended jail sentence as part of a deal with prosecutors after being accused of funnelling her earnings through a company in Andorra.
Her debut went down in opera history as one of the greatest overnight successes and she went on to tour the world in a career that spanned half a century.