In 1766 Spencer house was created for the first Earl Spencer who intended it for his childhood sweetheart, Georgiana Poyntz; he wanted a shrine built for her and Spencer House was the result. It has been a private residence since 1927 and was opened as a museum in 1990, and yes, he was an ancestor of Lady Diana, Princess of Wales. The Queen donated some furniture for the museum, and the Palm room is quite the ornate, decorated example of a royal family. The city of London recognizes it as the only eighteenth century private palace to survive the city's colorful and tragic history intact.
The private palace is located close to St. James Palace, Buckingham Palace and the Palace of Westminster. During the tour you will see splendid views of Green Park, complete with shrubbery and trees centuries old. The tour lasts approximately an hour on every Sunday. The maximum allowed on the tour is 20, so you can call ahead and reserve a spot. The front desk at any hotel you are staying at in London will be happy to put you in contact or schedule a reservation for one of the guided tours.