Speaking to the Sun, ahead of the episode’s airdate later this month, the ‘Strictly Come Dancing’ judge explained that there had always been “chat” about her grandfather, George Rich, potentially having black ancestry.
“People used to call him not such a nice name, which I won’t say, but it referred to the fact he was perhaps black,” she told the paper. “There was all this sort of chat that nobody really paid too much attention to.”
Shirley travelled to South Africa during filming and, working with the programme’s researchers on the trip, she found out her four-times-great-grandmother, Caroline Otto, arrived in the country in the 19th century after being taken from Madagascar and sold as a slave.
Caroline was a Muslim, and the show will see Shirley learn that Caroline had three children who she raised as Christian, while remaining Muslim herself.
Talking about what it was like to film the show, Shirley added: “It was heartbreaking, it was an emotional journey. There were a lot of tears.
“I’m quite a softie really. I go back and I try to imagine other people’s lives. It was nothing like how I set out on the journey.”
There have been 14 series of ‘Who Do You Think You Are?’, which have seen celebrities including Graham Norton, Kim Cattrall, Danny Dyer and Anita Rani explore their family histories.