Margaret Atwood penning sequel to 'The Handmaid's Tale'

Elisabeth Moss stars as Offred in Hulu's "The Handmaid's Tale" based on Margaret Atwood's book. (Hulu)

Margaret Atwood announced Wednesday she is writing a sequel to her dark, dystopian novel "The Handmaid's Tale" that serves as an inspiration for the popular Hulu show.

The acclaimed author made the announcement on Twitter, explaining that the upcoming book will be titled "The Testaments."

"Yes indeed to those who asked: I’m writing a sequel to The #HandmaidsTale. #TheTestaments is set 15 years after Offred’s final scene and is narrated by three female characters," Atwood tweeted.

She also revealed the book will be published in September 2019.

Atwood's book was turned into the Emmy Award-winning Hulu series of the same name. The show, which has aired two seasons, stars Elisabeth Moss, Joseph Fiennes, Yvonne Strahovski and Alexis Bledel, among others. The streaming service announced in May it would be renewing the series for a third season.

Margaret Atwood celebrates "The Handmaid's Tale" Best TV Drama win at the 2017 Emmy Awards with the show's cast. (Reuters)

Bradley Whitford, who played Commander Lawrence in Season 2, told Fox News in August he was thrilled to be a part of the show.

“I am the biggest fan there could be. I think what those women are doing on that show is a generational achievement in acting. I can’t believe how good they are. So for me to get the opportunity to go on, I felt like I got a guest shot on ‘The Godfather’ or something,” he told us at the Television Critics Association’s Summer Press Tour.

He added of his character, Commander Lawrence, “I was especially thrilled when I realized how complicated this guy is.”

Whitford recognizes that the show has drawn and intense reaction from viewers.

“It was thrilling for me…. There’s a lot of passion about the choices that [main character Elisabeth Moss] made, and it’s mostly just a testament to the power of the show and what it’s hitting in people and how it’s resonating with people.

“I find it hard to talk about how brilliant I think it is. I’m not kidding at all when I say I can’t believe I get to be on it. I mean, it’s unbelievable.”