Carole and Michael Middleton's son announced the news at the beginning of the year, revealing the cocker spaniel had "slipped away in my arms at home" after being together for 15 years.
During the past six months, James has often paid tribute to Ella on social media and has continued to proudly advocate for Pets as Therapy, a charity providing therapeutic pet visits to care homes, hospitals, schools and more.
This week however, he shared a beautiful illustration of him and Ella side by side, and opened up about how it's been for him since Ella's passing in January.
"Always by my side," he began the post, before adding: "It's been six months since Ella slipped away… Although I miss her greatly, I find comfort in knowing that she is always with me, and it gives me strength."
Talking about his happiness and wellbeing company for dogs, Ella & Co, he added: "Ella & Co was born out of my desire to give back to my loving dogs, to treat them with the highest quality food and make their lives as happy and healthy as they have made mine. This platform is a constant reminder of the beautiful journey I shared with Ella. I'm looking forward to continue sharing Ella's legacy with you all, giving back to our amazing dogs, and recognising the important role they play in our lives, which I hope will make her proud."
He ended the beautiful message by adding: "Thank you to @lucyclaireillustration for this amazing painting - it perfectly captures the bond I have with Ella. She truly is always by my side."
James is very close to his siblings, Pippa and Kate, and his parents, Carole and Michael, and has been supported by them since Ella's death.
Back in January, James opened up about Ella's burial to The Times, revealing that the Princess of Wales and her family had all attended.
"Burying her; that was the worst. It took me four hours because I knew once I had finished digging, that would be the final farewell. All the family came to say their goodbyes," he wrote.
He added: "I can’t speak for them but I believe she influenced their lives too. Lupo, Catherine and William’s dog, is one of Ella’s puppies. My sister Pippa and her husband have a pup from Ella, as do other family members."
It is likely that Ella's burial took place at home in Berkshire where James lives with his wife Alizée Thevenet at a sprawling country estate. The pair also have dogs Zulu, Inka, Luna, Mabel and Nala.
James also made a sweet tribute to his sisters, who he shared have "always been there during difficult times."
Adding: "They were at my side during the hardest of times as well. For that, I am forever grateful."
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