The Francis hotel in Bath, a Sutton Hotel Collection property, will undergo a £13m refurbishment in July.
This will see the renovation of all 98 bedrooms and suites and the addition of a thermal spa with three treatment rooms.
Plans are also in place to launch a new Townhouse Brasserie, which will showcase seasonal British cuisine.
Meanwhile, the lobby will be redesigned to include a snug for both members of the public and residents to relax.
The Francis hotel opened as Accor's second UK-based MGallery property in 2012 and joined the Sutton Hotel Collection for its launch in 2022.
The property was one of the first Georgian buildings to be built in Bath and was once home to the 18th-century architect John Wood the Elder.
William Gibbs, hotel director of Sutton Hotel Collection, said: "This transformation will not only create an even more compelling hotel stay for domestic guests, but also drive even greater interest from more international leisure and business tourists who are visiting Bath.”
Shaun Bowles, cluster general manager of the Francis Hotel, Bath, said: “Our vision is to create something incredibly special in the heart of Bath that offers truly personalised and curated experiences to guests."
The Sutton Hotel Collection also includes the Queens Hotel Cheltenham and the Castle Hotel Windsor.