James Middleton is reflecting on some of his earliest memories of Prince William — from his love for James’ dog Ella to learning that the royal was “just right” for his sister Kate Middleton.

In an excerpt from his forthcoming memoir, Meet Ella: The Dog Who Saved My Life, which was published by The Daily Mail on Sept. 14, the 37-year-old brother of the Princess of Wales remembered the early stages of William’s relationship with his sibling.

After detailing how he met his beloved dog and the namesake for his book in college, James wrote that he brought the eight-week-old puppy back to Berkshire to his family home, where the now royal couple were staying at the time. As he wrote, Prince William, 42, was already “a fixture in our lives” and “a welcome member of the clan.” James detailed that William also took a liking to Ella.

“I have not told him or Catherine about Ella. They know I am getting a puppy, but they don’t realize her arrival is imminent,” James wrote. “So I let Ella announce herself; place her on the doorstep and allow her to make her entrance. She bounds into the kitchen to introduce herself to Catherine and William.”

Prince William then smiled and told James that he “thought you sounded a bit sheepish about something when you phoned,” before James confirmed, “She’s mine.”

In early 2010, six years into the royal couple’s relationship, James was spending more time in London with his sisters and Ella, and he got to spend some some time with Prince William as well. “But I remember putting him through his paces when we first met,” James wrote. “Did he deserve my sister? He had to earn my trust.”

“It helped of course that William was so genuinely fond of Ella. When he first encountered her as a tiny puppy at Bucklebury, he was smitten. He’d had a black Labrador, Widgeon, as a boy, and when Widgeon died, he left an empty space. I felt William was pining for a dog when Ella was around,” he continued.

For Prince William, James wrote, Ella was “a good excuse to escape the fiercely competitive nature of the Middleton family” — specifically when they played the card game Racing Demon.

“William would flinch at our ruthless determination to win at all costs,” James wrote. “He’d be delighted to be the first out, and when no longer compelled to take part, he’d slink off to cuddle Ella. Better still, he’d absent himself from the game entirely. ‘James, does Ella need a walk?’ he’d ask before we’d even started dealing the cards.”

“My sisters and I would exchange a knowing glance: William, for all the competitive rigor of his military training, was happy to be a loser at cards,” he added.

In an additional excerpt from Meet Ella, James remembered the “terrific buzz throughout the country” over rumors that his sister was engaged years later. He and his family found out about a day before the news went public in 2010, when the Princess of Wales told him while they sat “in a corner, chattering quietly” at a pub near Bucklebury.

“William has been in our lives for so long and we’ve grown very fond of him. He feels like our older brother and he and Catherine are so clearly a good fit, just right for each other,” James wrote. “As we digest the news, I know I haven’t yet experienced the love they feel for each other myself. But I’m hoping one day I will.”

“There on the front page [of the Evening Standard in the following days] was a picture of Catherine in her blue dress,” James continued. “I tucked a copy under my arm and walked home with a sense that it was all quite surreal.”

Noting that William was “lucky” to be “marrying my capable, down-to-earth big sister,” James added that he “felt absolutely reassured” that they were in love. “It was beautiful to see how he brought out her confidence,” he wrote. “She’d blossomed. I knew he’d look after her, and he does to this day.”