When Kate, the Princess of Wales, was spotted publicly for the first time after undergoing surgery and a hospitalization in January, the person by her side was her mother Carole Middleton.
Two weeks after being spotted in the passenger seat of a car driven by her mother, Kate, the wife of Prince William, announced publicly that she had been diagnosed with cancer.
In July, in only her second public appearance since announcing her cancer diagnosis, Kate attended Wimbledon with her sister, Pippa Middleton Matthews, by her side, as well as her daughter, Princess Charlotte, one of her three children with William.
In a video message shared Sept. 9, in which she announced that she had completed chemotherapy, Kate was seen playing a card game alongside her mom and dad, Michael Middleton, and William and their three children.
That Kate's family members have been by her side during her recovery came as no surprise to royal watchers, who have long observed Kate's closeness with her family.
Kate's younger brother, James Middleton, wrote on Instagram after her cancer announcement, "Over the years, we have climbed many mountains together. As a family, we will climb this one with you too."
Here is what to know about Kate's immediate family members.
Michael and Carole Middleton, Kate's parents, wed over 40 years ago and soon after welcomed Kate and her siblings Pippa Middleton and James Middleton.
The Middletons raised their children in Bucklebury, a village in West Berkshire, England, where they still live today.
Kate, now a mother of three herself, has said previously that she and her siblings spent a lot of time outdoors as kids, and with their grandmother.
"I had an amazing granny who devoted a lot of time to us, playing with us, doing arts and crafts and going to the greenhouse to do gardening, and cooking with us," Kate said in a 2020 podcast interview. "And I try and incorporate a lot of the experiences that she gave us at the time into the experiences that I give my children now."
She continued, "As children, we spent a lot of time outside and it's something I'm really passionate about."
The Middletons, who met while they both worked at British Airways, raised their three children while building careers as entrepreneurs.
In the late 1980s, the couple started their own retail business, Party Pieces, a party supply company that they sold last year, according to the BBC.
MORE: Kate Middleton seen for 1st time since abdominal surgery and hospitalizationIn the years since Kate's wedding to William in 2011, the Middletons have been welcomed in by Britain's royal family, appearing at major royal engagements like royal weddings and the coronation of King Charles III and Queen Camilla last year.
Michael and Carole Middleton are also active in the lives of William and Kate's three children, Princes George and Louis and Princess Charlotte.
The Waleses' main residence, Adelaide Cottage, a four-bedroom cottage on the grounds of Windsor Castle, where they moved in 2022, is just over 30 miles away from Bucklebury.
In a 2018 interview with The Telegraph, Carole Middleton shared a family Christmas tradition involving the Wales children, noting that she puts up one separate Christmas tree just for her grandchildren to decorate on their own.
The Middletons are now the grandparents of seven, including George, Charlotte and Louis.
Carole Middleton told The Telegraph that she loves being a mother and a grandmother, saying that as a grandmother, her role model is her own mother-in-law.
"I had a wonderful role model in Mike's mother, who I tried to emulate," she said.
Pippa Middleton Matthews was born Sept. 6, 1983, and is Kate's second youngest sibling.
Matthews was famously Kate's maid of honor at her wedding.
Six years later, in 2017, Matthews became a bride herself when she tied the knot with hedge fund millionaire James Matthews.
The couple's wedding took place at St. Mark's Church, and the reception was held in the backyard of the Middleton family's Bucklebury home. Kate's children, George, then 3, and Charlotte, then 2, served as a pageboy and bridesmaid, respectively, in the wedding.
Pippa and James Matthews are now the parents of three young children, Arthur, Grace and Rose.
Matthews is an accomplished athlete who has participated in a number of sports challenges around the world with her husband and her brother, James Middleton. She has cycled across America for charity, run a 47-mile swim-run race and completed the Bosphorus Cross Continental Swimming Race in Turkey.
Kate's youngest sibling, her brother James, was born April 15, 1987.
In 2023, James Middleton became a first-time dad, welcoming a son named Inigo with his wife Alizée Thevenet, whom he wed in 2021.
Like his parents, James Middleton is an entrepreneur. In 2014, he launched a company called Boomf, which creates personalized marshmallows, greeting cards and gift boxes. Years later, he launched a second company, James & Ella, that manufactures dog food.
MORE: The latest on Kate Middleton as rumors swirl about her healthJames Middleton is the most public of the three Middleton siblings as he has a public Instagram account where he shares photos of his personal life, including a Mother's Day tribute to Carole Middleton last year.
A well-known animal lover, James Middleton has also been open about his mental health, sharing how he battled "crippling" depression after his family entered the public eye.
On the website for James & Ella, he credits his dogs with helping him survive the depression, writing, "A few years back, my dogs helped pull me out of a really difficult battle with depression. When I reached the other side, I set out on a mission to make their lives just as happy and as healthy as they've made mine, starting with the food they eat."