Ndileka Mandela has accused Harry and Meghan of "stealing" her grandfather Nelson Mandela's words for their gain with their Netflix documentary Live To Lead.
During the show, the Duke and Duchess of Sussex use footage of the anti-apartheid campaigner leaving prison in 1990, with Harry saying: "This was inspired by Nelson Mandela."
However, Ndileka has hit out at "upsetting and tedious" Harry and Meghan, telling The Australian newspaper: "They are using his quotes to draw in people and make millions."
She said she was angry the pair had drawn a comparison with their leaving behind the Royal Family and Mandela's walk to freedom after he'd been imprisoned in South Africa.
"That's chalk and cheese, there is no comparison. I know the Nelson Mandela Foundation has supported the initiative but people have stolen grandfather's quotes for years and have used his legacy because they know his name sells - Harry and Meghan are no different from them," she said.
"I admire Harry for having the confidence to break away from an institution as iconic as the Royal Family. Grandad rebelled against an arranged marriage to find his own path in life.
"But it comes at a price, you have to then fund your own life, I've made peace with people using granddad's name but it's still deeply upsetting and tedious every time it happens."
Mandela also said she was disappointed the Sussexes were apparently benefiting from this comparison.
"I don't believe he nor Meghan have ever properly met granddad, maybe when Harry was young at Buckingham Palace, but they are using his quotations in the documentary to draw in people and make millions without the Mandela family benefiting."
Live To Lead has already been rocked with controversy.
In December last year the trailer was released showing footage of New Zealand Prime Minister Jacinda Ardern.
Ardern said at the time she only found out when it was released that she was featuring in the Netflix documentary series - and she'd heard nothing directly from Harry and Meghan or Netflix about her inclusion in it.
Her office was told last year Netflix had secured the rights to broadcast an interview Ardern filmed with the Nelson Mandela Foundation in November 2019. Her office was then told earlier this year that the documentary would be presented by the Sussexes.
"The Mandela Foundation has kept the office up to date with what they have intended to do with interviews, but I have not stayed close to that, so I became aware of what was happening with it yesterday," she said at a press conference the day after the trailer was released.
However, this latest attack is not the first time the Sussexes have been blasted by Nelson Mandela's grandchildren.
In August last year, his grandson slammed Meghan for suggesting her marriage to Harry sparked as much joy in South Africa as the release of the anti-apartheid activist from prison after 27 years.
Markle made the comments to The Cut magazine as part of a wide-ranging interview.
She told the magazine that three years ago, a South African actor told her at the launch of the live-action Lion King movie: "I just need you to know: When you married into this family, we rejoiced in the streets the same we did when Mandela was freed from prison."
But Zwelivelile 'Madla' Mandela, the grandson of the activist, said the two could not be compared and the release of his grandfather was far more important than her marriage "to a white prince".
