However, the move has upset some of her North London neighbours, who described the plans as "tacky" and an "affront" to the 19th Century mansion formerly owned by poet Samuel Taylor-Coleridge and author JB Priestly, according to The Mirror.
One local resident said: "Kate lives in a blue plaque property, commemorating the fact that Priestly previously lived in it.
"As well as a tacky gym and steam room complex, there's going to be a basement kitchen. I dread to imagine the kind of smells that will be wafting up.
"She's also planning on installing a huge satellite dish which will look so ugly on top of such an old, sprawling house, as will all these new-fangled cameras. It's an affront to the blue plaque."
Moss's gym plans are said to be part of a proposed £2.5 million redevelopment of her Grade II listed home, which also includes building a third dressing room, installing a giant satellite dish on the roof and fitting eight security cameras.
The model shares the house with new husband Jamie Hince and her daughter Lila Grace.
