The 28-year-old 'Pride & Prejudice' star reportedly bought the estate in 2010 though it is registered under her mother Sharman Macdonald's name, reported Contactmusic.
She will reportedly marry Righton on the ground floor of the eight-bedroom property. Several tents have been erected on the farm and the couple have employed a local catering team for the reception.
Guests will indulge on 120 bottles of wine sourced from local vineyard Chateau Minuty.
"It's a beautiful location for the wedding. They're very, very lucky. It's just the perfect time of year for it as well, they couldn't have picked a better weekend weather-wise," a source said.
"It's all been a massively covert operation - her friends and family were only told recently about the ceremony. They've all been told not to travel in big groups, to arrive separately and to all spread out where they're staying so as not to draw attention to the wedding party," the source added.
The couple got engaged in May 2012 after meeting through mutual friend Alexa Chung.