SA's Thuso Mbedu is riding the train to international fame

In a parallel universe Thuso Mbedu might have been a 29-year-old dermatologist living and practising in her home suburb of Pelham, Pietermaritzburg.

As a young girl growing up in KwaZulu-Natal and afflicted by seasonal allergies that irritated her skin, Mbedu once dreamed of becoming the first member of her family to graduate as a doctor, much to her beloved grandmother's delight.

But, things didn't work out that way and today Mbedu is living in Los Angeles, riding the publicity roundabout for Oscar-winning director Barry Jenkins' hugely anticipated new Amazon Prime Video Series The Underground Railroad, starring Mbedu, the first South African actress in history to lead a US series.

She's also set to co-star with Viola Davis in her feature film debut The Woman King, an historical epic set in the legendary female warrior-led 19th-century Kingdom of Dahomey, which is to be directed by award-winning filmmaker Gina Prince-Bythewood later this year.

Adapted from the Pulitzer Prize-winning novel by Colson Whitehead, The Underground Railroad tells the story of the cross-country odyssey of Cora - a feisty, determined young woman left to fend for herself on a Georgia cotton plantation in the antebellum South after her mother makes a break for freedom.

When Cora, in the company of fellow slave Caesar (Aaron Pierre), hitches a ride on the fabled underground railroad - which in Whitehead's clever literary conceit is envisioned as a literal underground railroad complete with stations, station masters and an actual train - she begins a journey of self-discovery in the real America while constantly keeping one terrified eye over her shoulder for the equally determined and brutal slave catcher Ridgeway (Joel Edgerton), who's hot on her heels and obsessed with capturing her.

Mbedu's life story has similarities with the character of Cora. Her mother died of a brain tumour when Mbedu was four, leaving her and her sister under the care of their grandmother. Her father was an absence in their lives and the girls were raised by their strict granny.

Mbedu got the drama bug while in high school where she took a class and realised, as she recently told Elle magazine: "This drama thing really has the potential to change people's lives. It helped me heal. It helped me make sense of a world that I couldn't otherwise understand in my everyday life. So I was like, 'This is what I want to do' - and then I had to tell my grandmother."

After some convincing, Mbedu began to pursue her acting career in earnest, studying drama at Wits University and landing parts in local television productions including Isibaya, Scandal! and the teen drama Snake Park.

In 2015 she landed a major role in the teen drama series Is'thunzi. She received two International Emmy nominations in 2017 and 2018 for her role in that show and while in the US for the awards ceremony in 2018, she was encouraged by her agent to send an audition tape to Jenkins, who was casting the lead in The Underground Railroad.

Mbedu recalls: "At the very beginning all I knew about the story was what was in the audition sides, which I loved because inasmuch as the brief didn't say much about the character, the sides painted her as complicated, as layered and I knew that as an actress, a person, performing her would stretch me and grow me as an artist."

Jenkins was impressed by her audition tape and after meeting Mbedu told her that in his mind, she "was Cora".

Mbedu says she was initially very confused . "I hadn't read the book. In reading the book I felt very connected to the character. I felt like she'd given voice to parts of me I didn't know how to articulate. But I didn't immediately say, 'Oh. I see myself in her because of my life experience'."

Mbedu started learning about the history and experiences of slaves in the US. She began to see that the story was powerful and that needed to be told.

"When meeting Barry for the first time he was just a super-cool person. We didn't talk much about the story. He wanted to meet me, and in the test shoot he stretched me. But he's the type of person who cares about your opinion, so he'll open up the floor to hear what you have to say - that says a lot about him."

Shot over 116 days in Georgia in 2019 and 2020 - with an unforeseen six-month interruption due to the Covid pandemic - the production was exhilarating and physically exhausting, but Mbedu says: "On the days that it wasn't easy, Barry was there to remind us where the character was coming from and what was happening in the context of the story.

"He was in constant dialogue with Nicholas Britell, who did the score for the show, and he'd come to me and play a short track, saying, 'this is the mood of this scene'. Then I'd completely understand what he was trying to do with it and that made for an amazing experience with the character, finding her and allowing her to just be."

Mbedu sees her lead in the show as a proudly South African moment. She describes herself as "one who's always kept her head down and focused on what matters".

She acknowledges: "It was the support of South Africans, the way they received me, how they welcomed this opportunity for me by becoming my biggest supporters that made me realise that this moment is bigger than just me."

Ultimately she hopes South African audiences will take from the show something she realised early in her preparation process, which is that there's a lot she didn't know.

"I thought I knew something about the 'enslaved body' in America but I had a lot of unlearning to do to learn the truth. There's this great divide between African-Americans and Africans in general and I would like audiences to realise that this story is so much closer to home."

This was highlighted for her when Jenkins sent her audio recordings of formerly enslaved people, who spoke in broken English, an English you'd hear in South African townships or rural areas today.

"I realised that it wasn't just an African-American story but the story of Africans in America - we're closer than we realise. There's room for empathy, there's room for growth, there's room to learn so that we can all, globally, help in this conversation that could change the trajectory globally about the oppressed black body in the world today."

Her grandmother, who died in 2013, did not witness most of her meteoric rise to stardom, but Mbedu, who is religious, probably feels that she's somewhere smiling down on her and ruefully admitting that maybe dermatology wasn't the right choice after all.

• 'The Underground Railroad' is now streaming on Amazon Prime Video.