On 6 September 1766, her mother married secondly, and in secret, Prince William Henry, Duke of Gloucester and Edinburgh, a member of the British Royal Family as the younger brother of King George III.

[7] The year after Reynolds' painting was exhibited at the Royal Academy, Lady Elizabeth married her cousin, George Waldegrave, Viscount Chewton on 5 May 1782 at Gloucester House, Grosvenor Square, Piccadilly, London.

In the years following her marriage, Elizabeth gave birth to six children: She went to court on an unrecorded date where she served Charlotte, Princess Royal as a Lady of the Bedchamber.

When George III was incapacitated by mental illness in 1788 and 1789, she was one of the ladies who remained at the side of Queen Charlotte offering her loyal support.

[10] She died at the Gothic villa of Strawberry Hill in Twickenham (which had been inherited by her son the 6th Earl in 1797), on 29 January 1816 at the age of 55 and was buried beside her husband in Great Packington.