Royal experts credit Pippa Middleton as her sister Princess Kate's "backbone"

The Princess of Wales has been front and centre this summer, with the 42-year-old mother of three appearing to make a gradual return to royal life.

Princess Kate temporarily stepped back from public duties in 2024, recovering in private following the news of her cancer diagnosis. And while her treatment is still ongoing, the future Queen is reported to be making “good progress".

Royal experts have reported that Kate has been surrounded by a solid support network of loved ones during her recovery, with Carole Middleton, Prince William and the Wales children reportedly pulling out all the stops to care for her.

However, it is her sister Pippa Matthews, formerly Middleton, who is said to be one of Princess Kate's biggest supports, with royal experts crediting Matthews as the Princess of Wales' "backbone".

This was fully on display last weekend, with Matthews accompanying the Princess of Wales to her royal appearance at the Wimbledon Gentleman's Singles Final - Kate's second public appearance since her diagnosis.

"They were already genuinely best friends, but this gruelling year has seen them grow even closer," a source explained recently to The Daily Express. "Pippa has been something of an angel and backbone for Catherine.

"She's there at the drop of a hat, helping to pick up the slack on physical tasks when needed. But it's the emotional support she provides that is invaluable to Catherine.

Sources have even compared the bond of the Middleton sisters to that of the late Queen Elizabeth II and her sister Princess Margaret, with reports that Matthews will be selected as "Lady in Waiting" for her sister when Princess Kate becomes Queen.

"Like the bond shared between the Queen and Princess Margaret, they are genuinely best friends who understand each other and who Catherine can trust implicitly," the source continued. "And like Princess Margaret, Pippa is the more outgoing of the two sisters, but that only adds to her ability to support her sister in her royal role."

We will continue to update this story.