Harare, Zimbabwe CNN  — 

Oliver Mtukudzi, one of Zimbabwe’s most celebrated musicians, died Wednesday of an undisclosed ailment, a former colleague has said.

“He has rested. He had been in and out of the hospital since last year when he developed a heart problem,” Clive Mukundu, a music producer who worked with Mtukudzi, told CNN outside the private medical center where the 66-year-old musician was being treated.

A spokeswoman for his record label also confirmed the news to CNN.

Caroline Morabe said: “I can confirm that Oliver Mtukudzi has passed on. The family will release an official statement with more details later today.”

The soft-spoken star missed a prize-giving ceremony Tuesday, raising speculation that his illness had taken a toll.

Popularly known as “Tuku” by his fans, Mtukudzi had been successfully performing for decades throughout Africa, as well as in the United Kingdom, the United States and Canada.

Born into a musical family in 1952, his foot-stomping music has been described as a mixture of Zimbabwean pop style “jit” and South African township pop.

Through his distinct sound and inspiring lyrics, he documented the joy and pain of his countrymen who fought for freedom under colonial rule and died for democracy after Zimbabwe’s independence in 1980.

“Where I come from you don’t get to sing a song if you have nothing to say,” he said in a 2013 interview with CNN.

Mtukudzii grew up in Highfield, a ghetto neighborhood in the Zimbabwean capital of Harare. “So every song has something to do with that man in the street, he must be able to use it in his life,” he said.

The musician had more than 60 albums under his belt and released an album in 2013 titled “Sarawoga, a tribute to his beloved son Sam, who died in a car crash in 2010 at age 21. The pair often performed together and he described the album as “therapy” to help him get over the death.

“I was just thinking of him and trying to recover, even though music was my therapy. I think I’ve performed more shows since 2010 up to today than ever before because that’s the only therapy I’ve got.”

Often called the spiritual father of Zimbabwe, Mtukudzi, who lost his brother Robert and several band members to AIDS, campaigned to eradicate the HIV/AIDS stigma to mothers in Tanzania.

He was also outspoken against patriarchy and criticized polygamy as a practice that increases the risk of spreading HIV.

Damilola Odutayo contributed to this report