Stars including Dame Judi Dench, Imelda Staunton and Francesca Annis have all joined the follow-up to the autumn series.
The special will pick up life in the small Cheshire market town in September 1844 - a year after the marriage of Sophy (Kimberley Nixon) and Dr Harrison (Simon Woods).
Kate Harwood, the BBC's head of series and serials, and executive producer of Cranford, said she was pleased the ratings winner would be back.
"Cranford captured the hearts of the nation last year as every week, nearly 8m viewers tuned in to catch up with Miss Matty and her fellow villagers," she said.
"I am delighted that we are able to bring these much-loved characters back to life for a Christmas special in 2009 and once again uniting an unprecedented pool of talent to thrill and entertain our audiences."
The serial is nominated for four BAFTA Television Awards this year including programme of the year.