Catherine, Princess of Wales' dog has been a great source of support amid her cancer treatment

Asked if Orla will have supported Catherine through her illness, he told Britain's HELLO! magazine: "I know how much the dogs, for me, have helped in taking your mind off something. So I'm certain that for them, Orla is doing her job in supporting her family."

James - who has been open about his struggles with depression - also knows Catherine can rely on their family, as well as husband Prince William and their three children, for support.

He said: "We are certainly a close family that goes through things together.

"That was the experience I had through my challenges, and I certainly feel like it's something that her [Catherine's] family and our family are doing too."

However, the 37-year-old entrepreneur didn't initially confide in his family about his mental health issues until he sought help through therapy.

He said: "I needed to understand it myself, and I knew that my family wouldn't necessarily understand it."

James and his wife Alizee Thevenet are parents to 11-month-old son Inigo, and the Dog's Trust ambassador admitted parenthood changed his life forever.

He gushed: "No matter how much people say to you about how wonderful it is, or how it will change your life, nothing can ever prepare you for that experience of seeing a little baby that's yours arrive. It unlocks something in your heart that you didn't know was there."