London, UK - Shortly before the royal wedding of Prince Harry and Meghan Markle in 2018, things were boiling behind the walls of Buckingham Palace. Meghan's choice of tiara caused some trouble between Harry's bride and the late Queen Elizabeth – until the monarch put her foot down.

Almost eight years after the Sussexes said "I do," a new book has brought to light a fierce dispute that caused tensions in the royal palace in the run-up to the ceremony.

In his book Elizabeth II: In Private, In Public, The Inside Story, British author Robert Hardman reveals explosive details about a dispute between the bride and the then-Queen.

The reason for the row between Harry's wife and his grandmother: according to the Daily Mail, Meghan is said to have chosen a special emerald tiara from the royal estate for her big day, although its origin was not clear.

Because there were concerns in the palace that the precious jewel could possibly be linked to Russia, the Queen firmly refused the 44-year-old's wish.

The monarch's forceful response is also said to have infuriated her grandson, who demanded that Meghan get the tiara she wanted.

But she didn't get: in the end, the former actor had to settle for Queen Mary's Diamond Bandeau, a piece of jewelry from 1932 worth millions.

But that's not all: the situation is said to have escalated again when trying on the tiara.

Meghan had wanted to try on the expensive accessory together with her hair stylist, who had flown in from the US especially for the occasion, but Elizabeth's royal dresser, Angela Kelly, was able to prevent this.

"It's not a toy," was the Queen's sharp message to the bride and groom.

According to Hardman, choosing the wedding tiara was originally a nice tradition for the Queen as a way to connect with the bride.

In Meghan's case, however, it was clearly unsuccessful.