India, Aug. 2 -- Lady Eliza Spencer, Princess Diana's niece, is officially engaged to her longtime partner, Channing Millerd, after nine years together. The model and aristocrat shared the happy news on Instagram on July 31, posting romantic pictures from a sunset proposal in Santorini, Greece.

Lady Eliza, daughter of Earl Charles Spencer and Victoria Aitken, first met Channing Millerd in South Africa at a dinner party hosted by her now-brother-in-law, Greg Mallett, husband of her twin sister, Lady Amelia Spencer. Since then, their relationship has flourished, reported Hello magazine.

Spencer, speaking to the magazine, shared that she and Channing have a strong, loving, and supportive relationship. She said her fiance is "truly" her bes...