Oscar winner Reese Witherspoon will narrate the audio book version of Harper Lee’s long-awaited follow-up to To Kill A Mockingbird.

The actress, who won an Oscar in 2005 for her role as June Carter in the Johnny Cash biopic Walk The Line, will be heard on the audio version of Go Set A Watchman which is published in July.

The new novel, which is already a guaranteed best-seller, is the follow-up to Lee’s 1960 book about a rape trial in the racially-divided Deep South of the US.

Reese Witherspoon arrives for the British Academy Film and Television Awards 2015, The BAFTAs, at the Royal Opera House, in London, Sunday, Feb. 8, 2015
Reese Witherspoon (Jonathan Short/Invision)

To Kill A Mockingbird and its central characters, Scout, her brother Jem and their lawyer father Atticus, were brought to life in a 1962 film starring Gregory Peck.

Go Set A Watchman revolves around the now-adult Scout’s return to her native Alabama from New York to visit her father.

Reese, who was born in New Orleans, told USA Today: “As a Southerner, it is an honour and privilege to give voice to the Southern characters who inspired my childhood love of reading, Scout and Atticus Finch.

To Kill A Mockingbird author Harper Lee (Rob Carr/AP)
To Kill A Mockingbird author Harper Lee (Rob Carr/AP)

“I am eager for readers to be transported to a pivotal time in American history in the manner that only Harper Lee’s gorgeous prose can deliver.”

News of the new book’s publication stunned the literary world earlier this year and concerns were raised about the extent of Ms Lee’s involvement in the project.

Her agent was forced to respond to reports suggesting the 88-year-old was being taken advantage of over the publication of the book.

Authorities in her native Alabama closed their investigation into the issue saying the reclusive 88-year-old writer had “made it quite clear” she wanted the book published.