NCIS' Rocky Carroll on Henrietta Lacks and Working with Oprah Winfrey: Fans Will Be 'Really Surprised by Her'

NCIS' Rocky Carroll on Henrietta Lacks and Working with Oprah Winfrey: Fans Will Be 'Really Surprised by Her'

When Rocky Carroll heard that HBO was putting together a biopic on Henrietta Lacks, the NCIS actor jumped at the opportunity to be a part of the project.

“I had heard about the story of Henrietta Lacks a few years ago. A friend of mine read the book and told me about the story and I remember being amazed her story was true,” Carroll, 53, tells PEOPLE of the woman whose cells were the first successfully harvested by scientists, an act that has led to many medical advances in the decades since her death in 1951.

“This woman is one of the most important medical breakthroughs in medical history,” he says. “She’s still doing good and saving lives - and that’s incredible.”

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In The Immortal Life of Henrietta Lacks, Carroll stars as Lacks’ son Sonny opposite Oprah Winfrey as Lacks’ daughter Deborah.

“When she’s working as an actress, she is just one of the ensemble,” Carroll says of Winfrey, 63. “She’s incredibly giving and collaborative and that trickles down from her to the rest of the cast.”

“I think people are going to be really surprised by Oprah Winfrey in this performance. She’s such a persona and so bigger-than-life and to really see her take this character and dive in with both feet was really remarkable,” he says. “I was blown away by her and I was in the scenes with her, so I hope the audience will be too.”

The Immortal Life of Henrietta Lacks premieres April 22 at 8 p.m. ET on HBO.

This article was originally published on PEOPLE.com