But Rigby & Peller confirmed the loss of the Royal warrant.
June Kenton, director of the London-based firm, published Storm in a D Cup in March past year.
Kenton, from Bushey in Hertfordshire, bought Rigby & Peller with her husband in 1982 for £20,000, before selling a majority stake in 2011 for £8m, although she remains on the board.
"I never met Diana's boys, but I used to give her lingerie and swimwear posters for them to put up in their studies at Eton", Julie wrote.
When asked whether Buckingham Palace has over-reacted to the autobiography, she said: "Well I think so, obviously, because I've never spoken about a customer when she's come out of the fitting room".
"I think it's unbelievable", she added.
"I'm coming towards the end of my life, I'm 82, so it is what it is, there is nothing I can do". So maybe I was the Lord Chamberlain, not Buckingham Palace. It is not clear whether its decision to cancel the royal warrant is connected to the book's release.
Mrs Kenton, who started working for the Queen in the early 1980s, has been in the lingerie industry for more than 60 years. The book, she insisted, was not a tell-all but a celebration of the success of the business.
The book came out in March of previous year, but now Her Majesty has responded definitively (if not swiftly) by revoking the lingerie supplier's royal warrant.
The royal coat of arms must be removed from any promotional material and shop signs. "In respect of Royal Warrants, we never comment on individual companies", a palace statement reads. She's also a gifted rider, so her shoe collection is sure to include riding boots.