The Duchess of Cambridge joined her brother James Middleton as he battled depression through therapy sessions.
The 32-year-old, who suffers with depression, attention deficit disorder (ADD) and dyslexia, said family members including sister Kate attended his cognitive behavioural therapy sessions with him.
He described this as a "very big thing" for him, after years of being engulfed in mental darkness which made him feel like he could not speak to them.
James told the Telegraph : "The fact is, no matter what experience someone has, your family members are the hardest people (to talk to)."
During his lowest moments James was crippled by the mental disorder.
"I couldn't do anything," he said. "I couldn't sleep, I couldn't read a book, I couldn't watch a film, I couldn't eat. If I ate something it just sat there."
The Duchess's brother said he contemplated suicide, though he believes he would never have gone through with it.
At his lowest points he found solace listening to Stephen Fry's narration of Harry Potter audiobooks.
Thanks in part to the support he received from his family and his emotional support dog Ella, a cocker spaniel, James now feels he is finally in a brighter place.
The greeting care entrepreneur recently proposed to his girlfriend, French-born financial expert Alizee Thevenet, 29, in the Lake District.
He said he would not have felt able to pop the question in his previous mindset.
The royal's brother works as an ambassador for the charity Pets As Therapy to raise awareness about the healing effects pets can have on their owners' mental health.
Kate Middleton and her husband Prince William spearhead the Heads Together campaign with The Duke and Duchess of Sussex.
Its aim is to end the stigma around mental health.
For confidential support, the Samaritans can be contacted for free around the clock 365 days a year on 116 123.
