A royal engagement, indeed.

Princess Diana‘s niece Lady Eliza Spencer celebrated her engagement party in Cape Town, South Africa, nearly five months after Channing Millerd, who she had been dating for a decade, popped the question.

The 33-year-old—whose father is the late Princess of Wales’ younger brother Charles Spencer—gave her followers an inside look at the festive celebration by reposting a few snaps on her Instagram Story Dec. 22, which included her gorgeous Galia Lahav A-line mini dress that featured white floral appliques covering a sheer bodice and a square neckline. She paired the frock with sparkling pumps and a slicked back ‘do.

Channing, meanwhile, looked handsome in a blue linen shirt and white pants, while Eliza’s twin sister Amelia Spencer Mallett stunned in a pleated light green mini dress. Also there were their mother Victoria Aitken, their older sister Kitty Spencer, 34, and their half-brother Samuel Aitken, 22.

Eliza announced her engagement to Channing back in July, sharing photos from his picturesque proposal in Santorini, Greece, that showed off her teardrop-cut diamond ring that she captioned, “Forever and ever.”