Grantley Hall in North Yorkshire has joined Pride of Britain Hotels, effectively replacing the Farncombe Estate, which left the marketing consortium in June.
The consortium of independent-owned luxury hotels has a self-imposed limit of 50 member hotels "to guarantee quality and exclusivity". Additional members can only join when another property leaves the consortium.
It hit this limit earlier this year with the addition of the Royal Crescent Bath, replacing the Arch London, which is no longer an independent hotel following its relaunch under the new owner's Prince Akatoki brand.
The luxury country house Grantley Hall hotel opened in July following a four-year, £70m renovation of the Grade II*-listed historic property. It is also a member of the Relais & Châteaux consortium.
The much-anticipated 47-bedroom hotel, owned by Valeria Sykes, has a culinary offering including Shaun Rankin at Grantley Hall; the pan-Asian EightyEight restaurant; and the more relaxed all-day dining restaurant Fletchers, overseen by Craig Atchinson.
The property's Three Graces Spa includes an 18-metre marble-lined indoor swimming pool, an indoor-to-outdoor hydrotherapy pool, sauna, steam room and snow room.
General manager, Andrew McPherson, said: "This is an exciting time for Grantley Hall and we are delighted to have joined Pride of Britain Hotels and to be part of this prestigious collection of unique hotels."
Peter Hancock, chief executive of Pride of Britain Hotels, said: "Grantley Hall is an outstanding addition to Pride of Britain's collection of fine independent hotels in the UK and has quickly made a name for itself since opening this year thanks to huge investment in the property and a great team led by Andrew McPherson."