Buchanan, 57, coached his country to three successful Ashes campaigns from 2001 to 2006-07 (when Australia won 5-0), losing just once in 2005. He also aided the Australians in two triumphant World Cups in 2003 and 2007.
England regained the Ashes in 2009 but have not won a test series in Australia since Mike Gatting led them to that honour in 1986-87. The first test starts in Brisbane on November 25.
"I can confirm John Buchanan will be arriving in the next 48 hours," an England spokesman said on Sunday.
Buchanan, who also coached Middlesex in English county cricket, will assist England Team Director Andy Flower in his plans.
Buchanan is renowned for his technical theories and use of psychology, but has divided opinion. Former Australia leg-spinner Shane Warne remains an outspoken critic of Buchanan's coaching approach.
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