Mujica became a cult figure during his 2010-15 rule, known for giving away most of his salary and driving an old Volkswagen Beetle.
He remains a figurehead of the Broad Front, the leftist coalition in power from 2005 until it was ousted in 2019 elections by centre-right leader Luis Lacalle Pou.
Last October, Mujica resigned from frontline politics, quitting his Senate seat amid the coronavirus epidemic, saying a weakened immune system put him at risk and staying in the office was no alternative to going out and meeting people.