The Crown's Best Kept Secret: Kate Middleton and Prince William's Mysterious and 'Modest' Fourth Home No One Has Ever Seen

Catherine, Princess of Wales, and Prince William are well-known for their three royal homes, Kensington Palace (their base), Anmer Hall in Norfolk and Adelaide Cottage in Windsor Home Park.

However, the future king and queen also have a nicely tucked-away cottage called Tam-Na-Ghar located on the Balmoral Castle estate in Scotland.

Rather than residing in the estate’s castle, which is now often open to the general public, the future sovereign and his consort opt for Tam-Na-Ghar. The residence is a quaint three-bedroom lodge in a traditional Scottish style.

It was a gift to William from his great-grandmother, Queen Elizabeth the Queen Mother, in 2002, which is also the year she passed away. For over a decade, the Wales' have kept their retreat largely out of public view, with no publicly available images of the interior and some online images of the exterior.

The Prince and Princess of Wales' primary base, Adelaide Cottage is a bit bigger than TRH's Scottish home with 4 bedrooms. This makes Tam-Na-Ghar the Wales' smallest home.

This revelation follows reports suggesting the late Queen Elizabeth II once gave the then-Duke and Duchess of Cambridge an offer they couldn't refuse by offering the pair a chance to live in one of the monarchy's grandest castles.

According to Interior Therapist Suzanne Roynon, the estate's historic "negative energy" may have been a deciding factor in keeping the future king and queen away. The future King William V and Queen Catherine politely declined HM, which was likely no surprise to her as she too passed on living in Fort Belvedere upon inheriting it in 1952. Her late Majesty's cousin, Gerald Lascelles lived in the castle instead, by invitation of the monarch.

The Windsor Great Park estate was originally built in the 18th century by Sir William Chambers for King George II, and the fort was designed as a folly, which is a decorative building without a true defensive purpose. It served various functions over the years, including a summerhouse and a tea house.

Fort Belvedere is most famously associated with King Edward VIII. It was his residence from 1929 until his abdication in 1936 to marry Wallis Simpson, a twice-divorced American socialite. This event, known as the Abdication Crisis, was a significant moment in British history, leading to Edward's younger brother, King George VI, ascending the throne.

After the abdication, Fort Belvedere ceased to be a royal residence and has been privately leased to various individuals. The building and its grounds are not open to the public, maintaining a degree of privacy and exclusivity. It is part of the massive Crown Estate, which also oversees the deed for the Royal Lodge, a place notorious thanks to the King and Prince Andrew's current feud over the mansion.

InStyle reported on Tam-Na-Ghar.