Margaret Atwood and Bernadine Evaristo have jointly won the 2019 Booker Prize.
The judging panel decided to flout the rules and name two winners for the trophy, with chairman Peter Florence saying the five judges simply could not choose.
Canadian author Atwood scooped the prestigious literary prize for The Testaments, the follow up to her 1985 novel The Handmaid’s Tale.
She was the bookmakers’ favourite to take home the fiction trophy along with a £50,000 prize.
In her acceptance speech, she said: “Neither of us expected to win this.”
She tied with British author Evaristo, who won for Girl, Woman, Other, which follows the lives of 12 characters living in modern Britain.
Evaristo has become the first black woman to win the Booker Prize.
The two winners will now share the prize money.
Their victory was announced during a dinner ceremony at London’s medieval Guildhall on Monday night.
Mr Florence said both the winning books “address the world today and give us insights into it and create characters that resonate with us”.
Gaby Wood, literary director of the Booker Prize Foundation, says the judges were repeatedly told they could not name two winners but they “essentially staged a sit-in in the judging room”.
She has insisted the decision “doesn’t set a precedent”.
The Booker Prize has been split twice before, before Nadine Gordimer and Stanley Middleton in 1974, and between Barry Unsworth and Michael Ondaatje in 1992.
Ms Atwood’s dystopian novel picks up in Gilead 15 years after the first book, and is told from the perspective of Aunt Lydia, and two other women – Agnes and Daisy.
The heroine of The Handmaid’s Tale – Offred – does not appear in the novel, but is relevant to the storyline.
Atwood hasn’t confirmed whether she will be writing any further Gilead novels, but when asked by Time magazine earlier this year, she didn’t reject the possibility, saying “I never say never”.
The success of the 2017 TV adaptation of The Handmaid’s Tale starring Elisabeth Moss has led to a surge in interest in Atwood, and sale of her work.
Despite having been written over 30 years ago, the book has let many to draw parallels with today’s political climate, particularly around rights over women’s bodies.
The symbolic red gowns and winged bonnets, mimicking the costumes in the TV show, have been worn by protesters at marches around the world.
The Handmaid’s Tale was also made into a 1990 film starring Natasha Richardson.
It is the second time Atwood has won the Booker award, taking home the prize in 2000 for The Blind Assassin.
A prolific writer, she published her first novel in 1969, and has gone on to write 16 novels in total as well as collections of poetry, non-fiction, children’s books, short stories and one graphic novel.
Her novels frequently explore the themes of gender and identity, religion and power politics.
While she has won numerous awards for her work, and received international acclaim, Atwood once told Variety she was a terrible speller.
Atwood has also been shortlisted three times previously, making her the joint top author for the most nominations, alongside Iris Murdoch.
She is only the third woman to win in the last six years, with Northern Irish writer Anna Burns taking home last year’s prize.
Evaristo is of Anglo-Nigerian heritage and has published seven previous books.
Mr Florence said her novel Girl, Woman, Other gave a “wonderful spectrum of black British women today”.
“In that sense this book is ground-breaking – and I hope encouraging and inspiring to the rest of the publishing industry,” he said.
The four other authors up for the award were Salman Rushdie, Lucy Ellmann, Chigozie Obioma and Elif Shafak.
Founded in 1969, the Booker prize is open to English-language authors from around the world.
Winners benefit from a raised profile and dramatically boost in book sales.
The 2019 ceremony is the first since investment firm Man Group announced it was pulling out of sponsoring the award after 17 years.
Silicon Valley venture capitalist Michael Moritz and his wife, writer Harriet Heyman now sponsor the prize through their charity Crankstart Foundation.