For most of her adult life, Princess Diana lived in the double apartment on the north side of which London residence?

Diana, Princess of Wales (1 July 1961 – 31 August 1997), was a member of the British royal family as the first wife of Charles, Prince of Wales, who is the eldest child and heir apparent of Queen Elizabeth II.

Diana was born into the Spencer family, a family of British nobility with royal ancestry and was the youngest daughter of John Spencer, Viscount Althorp, and Frances Roche. She grew up in Park House, situated on the Sandringham estate, and was educated in England and Switzerland. In 1975, after her father inherited the title of Earl Spencer, she became known as Lady Diana Spencer.

She came to prominence in February 1981 when her engagement to Prince Charles was announced to the world. Diana's wedding to the Prince of Wales took place at St Paul's Cathedral on 29 July 1981 and reached a global television audience of over 750 million people.

After her 1996 divorce, Diana retained the double apartment on the north side of Kensington Palace that she had shared with the Prince of Wales since the first year of their marriage, and the apartment remained her home until her death the following year. She also moved her offices to Kensington Palace but was permitted "to use the state apartments at St James's Palace".