The actress Thuso Mbedu is the first South African to lead a U.S. TV series.

I’m breathing for the first time in a long time,” reads the pinned tweet on Thuso Mbedu’s account. The 29-year-old South African actress wrote the words in February 2019, three months before it was made public that she’d landed the coveted role of Cora Randall in Barry Jenkins’ series adaptation of Colson Whitehead’s Pulitzer Prize-winning novel The Underground Railroad that debuts May 14 on Amazon (review on page 52). Playing an orphaned slave who escapes a Georgia plantation — which Mbedu does with a quiet ferocity— makes her the first South African to lead an American TV series.

Before she won the part, “I prayed about it — I’m someone who believes in God,” she tells THR. “But to your friends, you seem crazy for having the dreams you have, for taking the risks you take.” Risks like leaving your small-town home in KwaZulu-Natal or spending your savings on a shot at the pilot season in L.A. or pursuing an uncertain acting career instead of a steadier one in dermatology, as her grandmother had encouraged.

An established name back home, Mbedu had twice been nominated for an International Emmy for the local drama series Is’thunzi. The Underground Railroad, though, was her first international audition.

But even before she’d landed the part, Jenkins told Mbedu she was Cora. “At the end of our first meeting, he looked at me and said, ‘I’m not saying you got it’ — because we hadn’t yet done the test shoot —‘but you are the character,’ ” she says.

Growing up under her grandmother’s care in post-apartheid South Africa, the actress shared with Cora the loneliness and rejection of losing her mother (who died when Mbedu was 4 after developing a brain tumour) and not knowing her father. To take on the role, she dove into research. “Barry had sent me audio testimonials of formerly enslaved people, and hearing them speak, in a broken English of people who’d lived into their 90s, made their story that much was closer to me,” she says.

Because of the subject’s weight and how much of herself she brought to Cora, Mbedu says she went to therapy after shooting wrapped: “She’s too heavy to carry in the real world.” Now L.A.-based, Mbedu — who next stars in Gina Prince-Bythewood’s The Woman King opposite Viola Davis — wrote to Jenkins after seeing all 10 episodes to thank him. “Going on Cora’s journey — she’s provided me healing for wounds I didn’t even know were there,” says Mbedu. “That’s what I hope, I pray, that whoever watches it will experience the same healing. People who need to feel like their voices are being heard.”