The National Trust is to have Clandon House near Guildford partly restored after a serious fire devastated the building last year.
It has decided to focus its funds and efforts on the ground floor, where the most architecturally significant parts of the building were, while the upstairs area will be used for exhibition and event space.
The Trust's director general Helen Ghosh said: "Our plans involve returning parts of the house to its 18th century glory whilst at the same time creating a building of beauty and relevance for the 21st century."
She added that it was possible to create a "purer, more faithful version" of the 18th century mansion than the original by sticking more strictly to the contemporary style of the time.
The mansion appeared in the 2008 film The Duchess, starring Keira Knightley, before the fire in April last year, which destroyed the roof and caused floors to collapse inside the building.
