Carrie Symonds wore a pink dress to wait for Boris Johnson outside Number 10 in July.
The dress was a bright pink gown from the label Ghost, and costs £120. It sold out completely after Carrie wore it.
Boris Johnson and Carrie are not married, in fact, the Prime Minister is still married to his ex wife who he is seeking a divorce from.
However, the couple do live together in Camberwell.
If they marry while Boris Johnson is in office it will make history at the first Prime Minister wedding.
What would fashion fan Carrie be likely to wear for such an occasion, which would likely draw much press attention.
Caroline Wolf, who is a personal stylist for influential businesswomen and has styled members of international royal families, told Express.co.uk: “If she were to marry Prime Minister Boris Johnson, I could imagine her in a dress that is understated yet sophisticated in its simplicity.”
In fact the stylist said that Carrie may well be inspired by another very famous wedding dress, like the bride from another recent famous wedding – Meghan Markle.
Caroline went on: “Minimalist, chic and elegant; perhaps in a bias cut slip dress similar to that worn by the late Carolyn Bessette, wife of the late John F Kennedy Jr.
“An accompanying sheer veil for her shoulders would finish the look perfectly. I would suspect she would choose an up and coming designer or one who shared her passion for conservation, such as Stella McCartney.”
Carolyn Bessette was another political bride, although like Carrie she had a high flying career. She worked as a publicist for Calvin Klein.
She married John F. Kennedy Jr. the son of President John F. Kennedy and First Lady Jacqueline Kennedy.
The married in September 1996 in a very private ceremony, conducted by candlelight, on an island off the state of Georgia.
The dress she chose was by Narciso Rodriguez, a Cuban American fashion designer, for Parisian fashion house Cerruti, and it was very simple, made of pearlescent crepe.
She wore the dress with a veil over a loose bun and a sheer white gloves.
It is not known what Carolyn’s dress cost, but Carrie could emulate the style with a Halfpenny London stretch-duchesse satin gown selling for £1,600 on Net-a-Porter right now.
The dress is iconic among fashion fans for its simplicity. In fact, it is said Meghan Markle’s wedding dress was inspired by it, and the Duchess of Sussex had said the gown was her dream dress.
Blogger and expert on Meghan’s style Amanda Dishaw said: “It’s a very plain silk dress and to be fair, at the time [Markle said this], I don’t think she knew she was going to be marrying into the royal family. That dress definitely wouldn’t fly in Windsor Castle.”
Meghan has called Carolyn’s dress “everything goals”.
The choice of Stella McCartney would also link Meghan and Carrie, as the Duchess of Sussex wore the ethical brand for her second wedding dress.
Grace Kelly’s wedding dress has also been hugely influential for brides.
Is was designed Helen Rose, a costume designer from MGM, fitting for the movie star bride.
At the time the gown was said to cost $7,266.68. Taking inflation into account this would be around $68,430.49 today, or £55,000.
There have been many copycat dresses throughout the years, inspired by the original fairytale Hollywood royal wedding.
Kate Middleton’s wedding dress had some striking similarities to Grace Kelly’s, including a lace bodice and a v-neck shape.