Sarah Ferguson, the Duchess of York, is the ex wife of Prince Andrew, also 58.
She is the mother of Princess Eugenie, 28, and Princess Beatrice, 30.
Her youngest daughter is set to tie the knot to her drinks ambassador partner in October.
On the One Show recently Sarah revealed how she expects Jack Brooksbank, 32, who has been with her daughter for eight years, will act.
The redheaded royal revealed her son-in-law to be is “the best”.
She told presenters on the popular BBC programme: “The good news is that Jack works for Casamigos Tequila, so I’m perfect.
“He’ll just hand me the tequila and say: ‘Come on, mother-in-law, down it!'”
Sarah Ferguson and Jack Brooksbank have a sweet friendship. He met Eugenie where the family often holiday in Verbier, Switzerland.
At the time of the big wedding announcement, the Duchess of York was not shy in expressing her excitement about becoming a mother-in-law.
The aristocrat took to Instagram with a thoughtful message about the couple. Sarah wrote: “A total embrace of goodness and joy.
“We love Jack and I am so excited to have a son, a brother and best friend.
“Eugenie is one of the finest people I know and so together it will be pure harmony.”
Will Jack Brooksbank and Princess Eugenie have a prenup arranged?
The British Royal Family has an estimated net worth of £68 billion, however, Eugenie won’t protect her assets.
Eugenie, who works for an art gallery, is reported to be worth £3.6 million.
Royal expert Kate Nicholl revealed that a prenuptial agreement is not the done thing in the royal set.
She said: “I don’t think members of the Royal Family sign prenuptial agreements.
“It’s commonplace with celebrity marriage, but this is not a celebrity marriage, it’s a royal marriage.”
The Harry: Life, Loss, and Love author also stated that she is certain that neither Prince William or Prince Harry signed documents when they married Kate and Meghan.