George Richard St John, 3rd Viscount Bolingbroke and 4th Viscount St John, styled The Honourable George St John from birth until 1787, was a British peer and politician. He became famous in his own lifetime for embarking on an extra-marital relationship with his own half-sister, Mary Beauclerk, that produced four sons. The two lovers had to leave England and live on the continent for a time.

Lady Diana Beauclerk was an English noblewoman and celebrated artist.