‘We now talk more openly about mental health as a family’ (Exclusive)

James Middleton, Princess Kate’s younger brother, may be related to one of the world’s most famous families, but on a rainy summer afternoon in Bucklebury, Berkshire, his attention is on another brood: his six lively dogs.

These puppies hold a special place in her heart, all descended from her first two beloved pets—the Middleton family dog, Tilly, and her beloved cocker spaniel, Ella, who passed away in 2023. Ella’s legacy lives on in Middleton’s moving and heartfelt new memoir, Meet Ella: The Dog Who Saved My Lifewill be released in the U.S. on September 24. (Read PEOPLE’s exclusive excerpt here.)

In the piece, Middleton, 37, shares how Ella helped him through his darkest struggles with depression, including a night in 2017 when he nearly succumbed to suicidal thoughts. Ella was by his side for many key moments in his life, from his sister’s royal wedding to Prince William in 2011 to Christmases with the late Queen Elizabeth and her role as matchmaker, leading him to his wife, Alizée Thevenet, 35, a French financial technology professional. The couple’s son, Inigo, born just months after Ella’s death, will turn one in October.

“It’s taken me on a journey,” Middleton tells PEOPLE of writing her book in this week’s issue of PEOPLE. “I hope my son is able to learn about his own mental health long before I do, so he doesn’t have to go through some of the very painful moments that I went through.”

Diagnosed with clinical depression, attention deficit disorder and dyslexia, Middleton now devotes his energy to James & Ella, his business dedicated to producing ethical dog food and championing the supportive role dogs play in difficult times. Middleton’s own struggles run deep, and on a harrowing night in November 2017, when he contemplated jumping from the roof of his London apartment building, Ella was his beacon of hope, pulling him back from the brink.

Her parents, Carole and Michael, and her sisters, Kate, 42, and Pippa Middleton, 41, were soon at her side.

“We now talk more openly about our mental health as a family. That’s a great thing,” he says.

Reflecting on his family’s reaction to the revelations in his book, he says, “A hug from a family member means more than words. We are a close family, but this has brought us closer together. I know they are proud of me for telling my story.”

Middleton first burst onto the international stage at Kate and William’s royal wedding in 2011, when, like his sister Pippa, he found himself in the spotlight. Despite his dyslexia, he honoured their request to read at the ceremony at Westminster Abbey. To prepare, he worked with voice coach Anthony Gordon Lennox before the big day (with Ella by his side).

“I became very passionate about it and really enjoyed the excursions that Ella, myself and Anthony took to learn how to read it,” he recalls.

Middleton called the wedding, which was watched by tens of millions of people around the world, an “out-of-body experience.”

“It was like a royal wedding that I wasn’t at,” he said. “It felt like I was at a family wedding.”

Although his brother-in-law is the future king, William is fully integrated into the Middleton family.

“William has been fantastic in offering advice and support and giving his views on the best approach to take,” he says.

Of his sister Kate, he adds: “I have immense love and respect for my sister. I support her in everything she does. I recognize that my life is getting attention because of who she is, and it’s taken me a while to adjust to that. But I’m proud of who I am. My sister just happens to be who she is.”

The Princess of Wales is also battling an undisclosed form of cancer. On September 9, she announced that she had completed chemotherapy and was “taking each day as it comes.” When she announced her diagnosis in March, Middleton publicly expressed her support on Instagram, writing, “Over the years we have climbed many mountains together. As a family, we will climb this one with you as well.”

Reflecting on the situation in a park near their childhood home, he says: “There are a huge number of people who suffer from cancer. It doesn’t matter who you are, it doesn’t matter what your education is. Life throws obstacles at you.”

He added, “We are a close-knit family. It’s always important to have support around you and not do things alone. Sharing your feelings helps bring people together. My love and support for my family is more than just a post on Instagram.”

Can’t get enough of PEOPLE’s royal coverage? Sign up for our free royals newsletter to get the latest on Kate Middleton, Meghan Markle and more!

For Middleton, his unwavering “rock” is his wife, Alizée, whom he met by chance at a Chelsea bar, thanks to Ella approaching his table. The couple married in an intimate ceremony attended by their closest friends and family in the South of France in 2021. Fatherhood followed shortly after Ella’s death. It’s “absolutely certain” that Ella (who is mother to Kate and Prince William’s first dog, Lupo) sensed that Alizée was pregnant. “And it was, in terms of timing, the right time to go,” Middleton tells PEOPLE.

“The last gift Ella gave me was to leave at a time when I was ready to let her go, in a way,” he adds. “Without her, I wouldn’t be here today. I’m very grateful for that.”