When Princess Diana walked down the aisle in 1981 wearing one of the most iconic bridal gowns in royal history, the world was captivated. But behind the scenes, the creation of that fairytale dress was cloaked in secrecy — right down to a carefully chosen codename.

In a new documentary titled Secrets of Diana’s Wedding Dress, airing in the U.K. on June 28, designer Elizabeth Emanuel reveals the extraordinary measures taken to keep Diana’s dress under wraps. Among the most surprising? A pseudonym used during the planning phase: Deborah Cornwall.

“We were very conscious of privacy and security,” Elizabeth recalls in the film. “So we gave her a fake name — we called her Deborah Cornwall. Isn’t that odd?”

A Codename with Royal Layers

Though it sounds fictional, the alias was likely inspired by one of the titles Diana assumed after marrying Prince Charles: Duchess of Cornwall. At the time, this title was little known publicly — Diana was most famously styled as the Princess of Wales.

Ironically, that same title would become more closely linked to Camilla, now Queen Camilla. Following her 2005 marriage to Charles, Camilla adopted the Duchess of Cornwall title instead of using “Princess of Wales,” out of respect for Diana’s legacy.

Secrecy in Every Stitch

The designers, Elizabeth and then-husband David Emanuel, were under immense pressure to protect the gown’s design from leaking. Every detail — from fittings to fabrics — was shielded from the press, and only a tight circle of trusted team members were involved.