The Princess of Wales' brother reveals 'quiet acknowledgement' the Middleton siblings once made

The Princess of Wales told her siblings, Pippa Middleton and James Middleton , that she was engaged to Prince William prior to their engagement being officially announced. Catherine's brother opened up about how he learned the news at a pub in his forthcoming book Meet Ella: The Dog Who Saved My Life .

In an excerpt published by The Daily Mail , James recalled, "There is a terrific buzz throughout the country because the rumour is spreading that Catherine and William are about to get engaged. Our family know a day or so before it is officially announced in November 2010. Catherine, Pippa and I go out for a walk with Ella and Tilly to our local pub in a village close to Bucklebury. We sit in a corner, chattering quietly. Catherine whispers the news and says it will become public in the next day or so. Pippa and I want to be visibly excited, but we have to tamp down our emotions so no one suspects a thing."

James revealed that he and his sisters made "a quiet acknowledgement that we’ll always be there for each other, look out for one another, support each other. No matter how crazy things get."

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"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. 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," James penned. "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."

On the morning that the Waleses' engagement was going to be announced, James shared that Catherine rang him to let him know. "I walk with Ella in Battersea Park savouring the secret knowledge and feeling a thrill of happiness for them. I remember tramping for miles that day and returning to our flat via Sloane Square Tube. The first edition of the Evening Standard was piled high. There on the front page was a picture of Catherine in her blue dress," James wrote in his book. "I tucked a copy under my arm and walked home with a sense that it was all quite surreal."

The Princess' brother continued, "I thought how lucky William was to be marrying my capable, down-to-earth big sister, and I felt absolutely reassured that they were in love. It was beautiful to see how he brought out her confidence. She’d blossomed. I knew he’d look after her, and he does to this day."

James' book about his late dog Ella is scheduled to be released on Sept 26. Meet Ella is described as "a love letter to man's best friend, and a beacon of hope to anyone struggling through hard times." Per Simon & Schuster , the book "traces the extraordinary bond between James and his beloved first pup, Ella. From their enchanting introduction to their many adventures, from Scottish mountain sides to royal weddings, their journey is marked by love, loyalty, and unexpected twists of fate."