The Da Vinci Code was Brown's fourth novel but the first to find huge sales
A sequel to Dan Brown's conspiracy theory novel The Da Vinci Code will be published on 15 September 2009.
The Lost Symbol will follow hero Robert Langdon through a 12-hour timeframe.
Brown described writing the new novel, which was originally set for release in 2006 as "a strange and wonderful journey".
The Da Vinci Code was released in 2003. It became a world-wide hit, selling 81 million copies and spawning a hit film starring Tom Hanks.
The book saw symbologist Robert Langdon investigating a murder in The Louvre museum in Paris, a trail which led him into the murky waters of Christian history.
Details of the plot of the new novel are being kept under wraps, but Brown's editor Jason Kaufman described the setting of The Lost Symbol as "a masterful and unexpected new landscape".
Brown added: "Weaving five years of research into the story's 12-hour timeframe was an exhilarating challenge. Robert Langdon's life clearly moves a lot faster than mine."
The Da Vinci Code was Brown's fourth novel and in the wake of its success his previous works also became best sellers - with the quartet now ranking as the UK's top four bestselling adult paperback novels of all time.
A film adaption of Angels and Demons, a previous Robert Langdon story, is due for release in May this year.