Reese Witherspoon says 'Where the Crawdads Sing' was an unexpected success because attention to detail was paid.

The 'Legally Blonde' star produced the big-screen adaptation of Delia Owens' best-selling tome, and she believes the film flourished despite not many people being aware of it because of its breathtaking cinematography and a stellar cast led by Daisy Edgar-Jones as self-raised murder suspect Kya.

She told The Hollywood Reporter: "Underdog stories are my favourite.

"This movie wasn't on a lot of people's radars - and it's counterprogramming, I know - but it's a return to real filmmaking.

"It's a heart-and-soul experience on film with beautiful sets and beautiful costumes and wonderful actors.

"It's almost nostalgic for what you wanted to see in the summer."

The plot follows the young woman abandoned by her family and left to raise herself alone in a North Carolina town.

She becomes a respected author but is accused of murdering her former boyfriend.

'Where the Crawdads Sing' was the most-sold fiction book on Amazon in 2019. Oscar-nominated screenwriter Lucy Alibar penned the script and 'First Match' helmer Olivia Newman directed.

Reese previously admitted she is "fascinated" by the story and lauded the book in her own Reese's Book Club.

Explaining what drew her to the film, the 46-year-old star said: "With a jaw-dropping mystery, stunning Southern setting, and endlessly fascinating female heroine at its centre, I loved this book the moment I read it and am so excited to join forces with Elizabeth and her team to bring Delia's truly moving page-turner to the screen."