But that's where the twist comes in: Big Grandpa is Nelson Mandela, the anti-apartheid legend.
Being Mandela, a new series premiering on Sunday, invites US audiences into the lives of Zaziwe Dlamini-Manaway and Swati Dlamini, the fashionable, 30-something granddaughters of Mandela and Winnie Madikizela-Mandela. The 94-year-old former South African president, who recently was treated for a lung infection and had surgery to remove gallstones, does not appear in the series but his controversial ex-wife – "Big Mommy" to her grandchildren – does and seems to relish it.
If the Mandela clan seems like an odd subject for a reality show, the granddaughters make no apologies.
"We get asked this question a lot. Is this not going to tarnish the name and is this not going to be bad for the name?" Swati Dlamini said in an interview in New York, where she and her sister were promoting the show.
"But our grandparents have always said to us, this is our name too, and we can do what we think is best fitting with the name, as long as we treat it with respect and integrity."
The 13-episode, first season – which will air on Cozi TV, a new network launched by NBC Owned Television Stations – follows the two women as they try to carry on the family legacy while juggling motherhood in Johannesburg.
Childhood spent in exile
The sisters, who spent most of their childhood in exile in the United States, make an emotional visit to the prison on Robben Island where their grandfather spent 18 of the 27 years he was imprisoned by South Africa's white-ruled government. Swati works on publishing the prison diaries that her grandmother wrote but now cannot bear to read.
The women, along with two brothers, also become the latest famous names to launch a fashion line, called "Long Walk to Freedom" in honour of their grandfather's autobiography. They hope that US audiences will see a vibrant and modern side of South Africa through their eyes.
The family, especially Madikizela-Mandela, loves to gossip about when Swati, the single mother of a four-year-old daughter, is going to get married. Swati is furious when Zaziwe, despite being sworn to secrecy, blurts to their grandmother that her sister is dating someone. Zaziwe (35), is married to an American businessperson and has three children.
The sisters are the daughters of Zenani Mandela and Prince Thumbumuzi Dlamini of Swaziland. But parents everywhere will delight in seeing that being royal doesn't help them face toddler tantrums or get older children out of bed and into school uniforms.
Big Grandpa and Big Mommy are into the show, the sisters insisted.
Mandela will definitely watch it, they said. The Nobel Peace Prize winner apparently likes reality TV.
Mandela 'loves Toddlers & Tiaras'
"You'll be interested to know that he loves Toddlers & Tiaras," said Swati, laughing in reference to the TLC series about child beauty pageants.
"Because of the kids! He just loves children," Zaziwe added quickly.
The sisters said their grandfather is "happy and healthy".
Zaziwe showed a February 2 photograph of Mandela at home, flashing his familiar smile, with his youngest great-grandchild on his lap – Zaziwe's one-year-old son. The picture is a rare public image of Mandela, whose last appearance on a major stage was during the 2010 World Cup soccer tournament in South Africa.
Mandela, who always lamented his long separation from his family during his imprisonment, is happiest these days when his offspring are running around being loud, his granddaughters said.
"We're in and out of the house. We're loud and he loves the noise," Zaziwe said.
The granddaughters say their grandfather – to the world, a symbol of integrity and magnanimity – holds the family to high standards and sets rules for when the children should be home and when dinner should start.
"He's a very strict person. Most people wouldn't think that but he really, really is," Zaziwe said.
The doting matriarch
The sisters are closer to Madikizela-Mandela, who divorced Mandela in 1997. Their adoring description of their grandmother as the doting matriarch stands in contrast with her checkered public image. Madikizela-Mandela also faces accusations that she and her bodyguard unit committed 18 killings in the 1980s, which she has denied.
"She's fun. She never says no to us. I don't think I've ever heard my grandmother say no to us," Zaziwe said.
The sisters say it was only after Mandela retired from public life that they started to get to know their grandfather.
"Our grandfather always told us that he belongs to the country and he's of service to the country and he doesn't belong to us as a family. And that's the sacrifice he's made for the country and that what he's told us as far as I can remember," Swati said. – Sapa-AP