Filming is currently taking place at the Wimpole Estate.
Parts of the National Trust owned estate in Arrington, South Cambridgeshire, are off limits to the public while the production crew is on site.
Filming started last Thursday (April 22) and is due to last until Wednesday, May 5.
The National Trust is remaining tight-lipped over what the project is.
Rebecca Evans, of the National Trust’s Wimpole Estate, said: “There is filming taking place at Wimpole between Thursday 22nd April through to Wednesday 5th May on the wider estate.
"Unfortunately, we’re not able to reveal any details of the filming.
“We are always looking for ways to fund the vital conservation work that we need to do at Wimpole. The location fee for this film will go towards fundraising for this essential work.”
The farm, park, gardens and shop are now open at Wimpole. Visits can be booked by timed ticket.
A statement on the National Trust's Wimpole Estate webpage states: "Some areas of the wider estate are currently being used for filming.
"We are sorry for any disruption to your visit."
Visit www.nationaltrust.org.uk/wimpole-estate for more on Wimpole.
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