Rhumba musician and his son had been sentenced to life for raping 10 schoolgirls.
Tanzania's President John Magufuli has pardoned famous singer Nguza Viking, known as Babu Seya, and his son who had been jailed for life for rape.
Viking and his son Johnson Nguza, also a musician known as Papii Kocha, were among the 1,828 prisoners granted presidential pardon.
Addressing the country at the 56th Independence Day fete in Dodoma on Saturday, Dr Magufuli said the Constitution gives him the power to pardon any person jailed for any offence.
He also reduced prison terms for another 6,329 inmates.
Congolese-born Viking, who has lived in Tanzania for years, was sentenced in 2004, together with his three sons, for raping 10 primary school girls in 2003.
Two of the sons, Nguza Mbangu and Francis Mbangu, were acquitted in 2010 following an appeal.
However, the court upheld the conviction of Viking and Johnson. They appealed again, but lost in 2013.
The rhumba musician’s case attracted a lot of public attention including that of politicians.
Opposition Chadema presidential candidate Edward Lowassa had promised to forgive Viking and his son if he won the 2015 General Election.
But he lost the election, which was won by Dr Magufuli of Chama cha Mapinduzi (CCM).
The president also granted clemency to 61 death row inmates.
“Some of those prisoners who have been charged for death sentence are aged above 80 years. They have been in prison for over 45 years. In accordance with Section 45 of the Constitution, I want them to be released today,” he said.
Tanzania has over 39,000 prisoners, out of whom 2,000 are female and 37,000 are male, according to Dr Magufuli.