She sold her historic Sydney property, Bulwarra, in Hunters Hill last year having listed with hopes of $20 million to a buyer from China.
The new UK home sits on five hectares of English countryside, not too far from their former Brighton terrace house.
Highwell House, located in the small town Crowborough, has seven bedrooms, seven bathrooms and five reception rooms.
The home had fallen into disrepair, but renovated and restorewith bespoke materials and hand crafted finishes.
A 19th-century French chandelier hangs in the reception hall, with a large oak staircase leading up to the second level.
Featuring large bay windows and Belgian stone kitchen sink, work tops and tiling, the home also comes complete with turret.
It was 2003 when Blanchett paid $3.7 million for a home in Brighton, East Sussex, after deciding Islington, London was an unsuitable environment for baby son Dashiell.
The Regency house overlooked the English Channel.
It is said that author Lewis Carroll saw a white rabbit bounding down the tunnel on the grounds of the property in the 1860s, inspiring him to write Alice's Adventures In Wonderland.
Early last year they bought the city apartment of Wizard founder Mark Bouris in the historic Astor building as their Sydney bolthole.
Cate Blanchett and director husband Andrew Upton purchased the sandstone waterfront Hunters Hill trophy home in 2004 for $10.2 million.