A 10-hour production of Leo Tolstoy's epic novel War and Peace will dominate BBC Radio 4's output on New Year's Day.
The new dramatisation by playwright Timberlake Wertenbaker stars John Hurt, Simon Russell Beale and Lesley Manville.
The radio adaptation will run between 9am and 9.30pm, with breaks for news and The Archers.
Radio 4 controller Gwyneth Williams described War and Peace as "arguably the best book ever written".
"If you haven't made the journey through it, Radio 4 thinks you are missing out," she said at Thursday's launch of the station's Christmas schedule.
Other shows over the festive period include a 90-minute Archers spin-off on Boxing Day and Terry Pratchett and Neil Gaiman's apocalyptic adventure Good Omens.
War and Peace is the longest drama that BBC Radio 4 has rolled out over the course of a day. On Boxing Day in 2000 it cleared the schedule for an eight-hour reading of JK Rowling's Harry Potter and the Philosopher's Stone. In 2012 there was a five and a half hour dramatisation of James Joyce's Ulysses.
War and Peace will be accompanied by a live running commentary on Twitter and a website with family trees, maps and historical trivia. R4's regular schedule will continue on long wave.
Wertenbaker said: "I always felt radio could do something with this great novel that film and television might not. The novel is full of reflections on the purpose of life, on history, on the strategic confusions of war and the emotional ones of peace.
"Throughout the book, you feel Tolstoy's probing mind and heart, searching, searching - radio can give you that time."
Drama commissioning editor Jeremy Howe said the drama took almost a month to record and "had all the logistics of a film shoot" with some scenes being recorded during a battle re-enactment in the Czech Republic.
He said: "It's one of those books that, once you've got into it, it's very hard to get out of and we wanted to replicate that extraordinary reading experience."
The Archers Christmas spin-off sees characters from the Ambridge-set radio soap perform in a 90-minute version of Blithe Spirit.
Noel Coward's play tells the story of a novelist haunted by his dead wife. The famous role of eccentric clairvoyant Madam Arcati will be played by Archers am-dram queen Lynda Snell (Carole Boyd).
The standalone drama follows the build-up to the performance during regular editions of The Archers. As well as other Archers regulars, the cast will also feature Green Wing actor Julian Rhind-Tutt.
The dramatisation of Neil Gaiman and Terry Pratchett's cult novel Good Omens airs on 22 and 27 December with a cast that includes Mark Heap, Peter Serafinowicz, Colin Morgan and Josie Lawrence.