Princess Diana had mentioned Prince William and Prince Harry's family in her will.

According to Madhvi Mavadiya, a journalist for Daily Mail, the late People's Princess had a discretionary fund that was formed for the Duke of Cambridge and Duke of Sussex, their spouses, descendants, charities and co-trustees. It received the assets of the estate, intellectual property rights, wearing apparel, $130,240 and accumulated income earned by the fund assets.

"The income earned by the fund is to be distributed among the fund's beneficiaries during the Perpetuity Period as the trustees see fit. Anything left in the fund when it expires will go to the then living descendants of Prince William and Prince Harry," the report stated.

In addition, Princess Diana mentioned that she wanted her jewelry to be used by her daughters-in-law. She also made it clear that these assets will be divided equally between Prince William and Prince Harry.

"But I would like you to allocate all my jewelry to the share to be held by my sons, so that their wives may, in due course, have it or use it. I leave the exact division of the jewelry to your discretion," she wrote in her Letter of Wishes, according to The Telegraph.

At the time, Middleton has Princess Diana's engagement ring. Prince William confirmed that he used his mom's ring when he popped the big question to Middleton.

"It's my mother's engagement ring, and it's very special to me, as Kate is very special to me now as well. It was only right the two were put together. It was my way of making sure mother didn't miss out on today and the excitement," Prince William said.

Also, following the Duke and Duchess of Cambridge's royal wedding, Middleton has been seen wearing the Lover's Knot Tiara. The said headpiece was a wedding gift to Princess Diana from Queen Elizabeth.

Middleton also inherited Princess Diana's sapphire earrings, which have been updated to a drop style. The royal mother of three was also seen wearing a pearl bracelet.

Aside from getting the chance to wear Princess Diana's precious items, Middleton will reportedly inherit her title, too. When Prince Charles takes over the throne, Prince William will be the next Prince of Wales and Middleton the Princess of Wales.