Pretty Yende (File Photo: AFP)
The 38-year-old says her performance in Westminster Abbey will mark the first time an African singer has performed solo for the coronation of a British monarch.
"I feel very, very honoured because it is something that has never happened before," she told AFP.
"Generations from now they will read about the British monarchs... and they'll see the name of a girl from the tip of Africa written in there -- that she was actually invited by the king himself to sing at Westminster Abbey."
Yende, born at the height of apartheid in 1985 in a township in eastern South Africa, would sing traditional Zulu songs on the way to church and gospel music with the choir.
It was hearing Leo Delibes's operatic "Flower Duet" on a British Airways advert that changed her life.
Opera "is a gift to humanity and there's something divine about it too", Yende said, adding that she hoped her performance would encourage more people to try it.
Some critics have called on her to boycott the coronation in protest at Britain's colonial past, but that is not her style.
"I see each and every opportunity I get as a possibility for my gift to reconcile, to heal, to love, to give joy, to give hope and to give dreams for the future," she said.
"We cannot change the past but each generation... with a small action can give hope for tomorrow."
'Dream come true'
Yende, who will sing a new piece by British composer Sarah Class, "Sacred Fire", has been in demand at the world's leading opera houses for a decade, with critics praising her charisma and luminous, bel canto timbre.
Charles III, a classical music fan, saw her perform at Windsor Castle a year ago when he was still Prince of Wales.
"It's a dream come true, because when I found out that I have this incredible gift I wanted to share it with as many people as possible," Yende said.
Active on social media, sharing positive messages to her legions of #PrettyArmy fans, she says she is excited for the big day.
"I am counting the hours now. The preparations are going very well and I can't wait," she said. "I know that my life will no longer be the same."
Yende's will not be the only unprecedented performance, with Bryn Terfel set to be the first to sing in Welsh at a coronation.