Hannah, whose TV work includes Richard and Judy, 60 Minute Makeover and GMTV, will be setting off for the week-long Gobi March 2009 on 14 June.
Each competitor must carry their own food and clothing in a backpack as they trek across the Chinese desert.
The Shire Horse Society, established in 1878, said it is honoured to receive Hannah’s support.
In the 18th and 19th centuries the UK had a heavy horse population of well over a million but by the early 1960s this had dwindled to a few thousand.
The Shire Horse Society, working with a growing number of breeders and enthusiasts, has gradually numbers again.
To sponsor Hannah, send a cheque, made out to The Shire Horse Society, to Gobi March, The East of England Showground, East of England Agricultural Society, Peterborough. PE2 6XE.