James Middleton Thanks His Dog for Getting Him Through 'Insufferable Darkness' on Mental Health Day

James Middleton continues to speak with raw candor about his battle with depression.

Kate Middleton‘s younger brother, who recently announced his engagement to French financial analyst Alizee Thevenet, shared a photo of his black cocker spaniel Ella on Instagram in honor of World Mental Health Day, the global initiative to spread awareness and stop the stigma surrounding mental issues on Thursday.

“This is Ella & these are the eyes which helped me get through the insufferable darkness 🐾 👁 ,” he captioned the photo. “The gentle touch of your wet nose and a loving lick was enough to make me feel brave. I will forever be in your debt. Thank you Ella 🐾 ❤️”

In a op-ed for the Daily Mail published early this year, James opened up about his battle with depression, recounting his darkest moments before seeking treatment a little over a year ago. He also credited his dogs with providing emotional support.

“I recognize, too, the role my dogs — Ella, Inca, Luna, Zulu and Mabel — have played in my recovery,” he wrote.

“Ella, particularly, has been my constant companion for ten years and she’s been with me to all my therapy sessions. In her own particular way, she has kept me going,” he continued. “As a result, Ella and I now volunteer with the Pets As Therapy charity and Ella is a fully-fledged therapy dog for PAT.”

In fact, James brought Ella as his date for the GQ Men of the Year Awards in London last month. The pup walked the red carpet sporting a black and tartan “Pets as Therapy” jacket to represent a UK animal therapy charity.

RELATED: James Middleton’s Stolen Dog Bike Has Been Found — and He’s Paying It Forward in the Best Way

In his op-ed, James recalled how he would struggle to get through the day during the worst of his depression.

“During the day I’d drag myself up and go to work, then just stare with glazed eyes at my computer screen, willing the hours to tick by so I could drive home again,” he wrote. “Debilitating inertia gripped me. I couldn’t respond to the simplest message so I didn’t open my emails.”

“I couldn’t communicate, even with those I loved best: my family and close friends,” James continued. “I know I’m richly blessed and live a privileged life. But it did not make me immune to depression. It is tricky to describe the condition. It is not merely sadness. It is an illness, a cancer of the mind.”

James, 32, later revealed his reason for speaking out on his experience is to help change the stigma associated with mental illness.

In addition, James felt compelled to follow the lead of his sister Kate, brother-in-law Prince William and Prince Harry, who have been strong advocates for mental health.

“They believe we can only tackle the stigma associated with mental illness if we have the courage to change the national conversation, to expel its negative associations.”

In honor of World Mental Health Day, Harry also teamed up with singer-songwriter Ed Sheeran for a fun video shared to his @SussexRoyal Instagram page. The short clip shows Sheeran meeting up with the prince in order to talk about an issue he thinks they have in common: being teased for having red hair.

“I’ve been trying to write a song about this to get it out to more people,” the hitmaker tells the royal. “People just don’t understand what it’s like for people like us — with the jokes and the snide comments. I just feel like it’s time we stood up and said, ‘We are ginger, and we are going to fight.’ ”

Harry chips in and corrects him, “Um, okay. This is slightly awkward. There may have been a miscommunication — this is about World Mental Health Day?”

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

When the singer realizes his mistake, he quickly deletes the title of his song — “Gingers Unite” — on his computer.

The pair then turn to the serious message: “Reach out, make sure your friends, strangers, look out for anybody that might be suffering in silence. We’re all in this together,” Harry says directly into the camera. “Cheers.”