Shirley Ballas on discovering the tragic truths behind her family history on Who Do You Think You Are?

• Strictly Come Dancing 2018: All the celebrity rumours
• Strictly's Neil Jones explains why he STILL might not have a partner this year

But instead of a family history akin to the glitz and glamour of the ballroom, the Strictly Come Dancing judge actually uncovered several unexpected and decidedly painful stories in her lineage.

Abandonment, slavery and illness are unearthed as Shirley traces her ancestors from Liverpool all the way to South Africa and America.

Shirley explains that one of the stories passed down her family was of her maternal great-grandmother Clara Sutton who supposedly abandoned her three children – including Shirley’s grandmother, Daisy.

“She was irresponsible, ran off to America and was this party woman,” Shirley tells us. “She left her husband George and he died of a broken heart. At least, that was the story that was passed down through everyone in my family.” The truth, as she discovered while filming this episode, was very different.

“George actually died of multiple tumours,” explains Shirley. “He left all of his money to his mother, Elizabeth – my great-great grandmother – and nothing to his wife or children.” George passed away at the age of 36, when Daisy (Shirley’s grandmother) was just nine years old.

“So through all this, I suppose Clara didn't have an income and perhaps she decided her children would be better off with Elizabeth and that they would have a better life.” Not only that, but Shirley later discovers that Daisy did have an opportunity to go and live with Clara in America later on – but turned it down.

“My grandmother died never really knowing the truth,” explains Shirley. “And I think that's quite sad.”

American census records from 1920s show Clara remarried and lived with new husband Arthur Spidle in Boston, after sailing from Liverpool to New York the previous year. The episode sees Shirley growing emotional as she discovers that Clara and Arthur’s marriage was abusive and that they separated nine years after marrying.

“Two years later she was granted this divorce, and she was diagnosed with a brain disorder due to syphilis,” the 57-year-old explains. “She lived for 17 years in an institution and she died aged 66 from the syphilis.

"She just wasn't this woman everyone said she was,” Shirley concludes. But her journey doesn't end there.

She also investigates her father’s side of the family. “My dad left when I was two and I didn't know too much about his family,” she says. “The rumour through his family was that we might have black ancestry, so I was quite curious about that.

“I know that my great-grandfather – George Rich – was born in Cape Town in 1866 and it set my journey off to go to Cape Town to discover and find out more.”

The search leads Shirley to a woman named Caroline Otto – her great-great-great-grandmother. She discovers that Caroline converted to Christianity from Islam and Caroline’s parents, it transpires, are likely to have been brought to Cape Town as slaves from Madagascar.

“It was a moving and riveting journey,” reflects Shirley. “And really quite sad.”

Through these ancestors, Shirley recognises a strength of character that she sees not only running through her heritage, but also within herself.

“Strong women like Clara, she stood up for her rights,” she explains. “And I would have thought back then a lot of women wouldn’t have done that.

“And again, on my father’s side of the family there appears to be strength in the women all the way along the line. Even today my auntie Barbara, my dad's sister, is a real woman of strength. So it appears that has come through all the decades and down the lines.”

How did Shirley's mum, Audrey – who still lives in her hometown of Leasowe, Merseyside – react to her daughter's findings? "To be quite honest, she was absolutely in shock.”

But the Strictly judge was glad to be able to "set the record straight" on some of the stories that have been passed through her family. Not only that, but she learnt something important herself, too. “I don’t think anyone should assume anything about someone else’s life."

Who Do You Think You Are? with Shirley Ballas airs Monday 30th July at 9pm on BBC1