Princess Kate's Brother James Middleton Thought the Prince and Princess of Wales "Were Joking" When They Asked Him to Participate in Their Wedding

Princess Kate's brother James Middleton is opening up about the Prince and Princess of Wales' royal wedding and the nerve-wracking request he says he couldn't believe they made.

In an excerpt of his upcoming book Meet Ella: The Dog Who Saved My Life, recently published in the Daily Mail, Middleton recalled not only his battle with depression that led to suicidal ideation and his time with the former Queen and the "granny-sized void" she filled in his life—he also revealed how surprised he was when Prince William and Princess Kate asked him to read a passage from the Bible during their 2011 wedding at Westminster Abbey.

"The wedding was barely eight weeks away when Catherine and William, on the phone together and ­bubbling with excitement, asked me brightly if I might be up to doing a reading on their big day at Westminster Abbey," Middleton writes.

"A reading? I thought they were joking. My mind raced back to school and my stumbling, ­incoherent efforts to read in front of the class. What were they ­thinking? Being dyslexic, reading is my least favorite occupation," he continued. "‘Seriously?’ I asked. ‘Seriously,’ they chorused. Oh no! I thought."

While apprehensive and still in disbelief, Middleton writes that he agreed to do the reading, hiding his true feelings from his sister and her soon-to-be husband.

"‘No problem at all!’ I fibbed breezily. If that was what my sister and William wanted, then of course I’d do my best not to let them down," he explains. "Then they added: ‘This will be the only Bible reading in the service,’ and I didn’t know whether to be honored or appalled."

To prepare for his big moment (when all eyes were fixated on the royal family), Middleton writes that he carried the reading "with me everywhere, taking it out of my pocket to practice the lines." He went on to explain that he "tripped and stumbled, transposing syllables, getting my ps and bs—my nemesis—in a twist."

In addition to practicing in front of others and in venues that would help Middleton get used to the acoustics of Westminster, Middleton says he also practiced the reading out loud to his dog, Ella, who he credits with saving his life in the book.

"Back at the flat, I practiced again and again, declaiming from my now crumpled sheet of phonetic text. Ella sat patiently on a chair in front of me. I’d occasionally put her name into the reading so her ears would prick up," he writes. "I recorded myself doing the reading, and on long walks with Ella I’d listen to these recitals. Sometimes I’d say the words out loud as we walked."

Finally, the day of the wedding arrived, which Middleton details including the moment he delivered the reading to the happy couple, the wedding attendees and the world.

"I walked up steadily to the lectern and stood, poised to begin. But where was my scruffy piece of paper? I couldn’t see it. Had it been thrown away? Panic almost overwhelmed me," he writes, before adding that once he "turned the page of the Bible" in front of him he found the paper, discretely hidden.

"Relief washed over me," he continues. "I waited until the great Abbey fell silent. Ten, perhaps even 15 seconds. Then I counted slowly to four and all that could possibly go wrong flooded into my mind. Were my flies undone? Would I have a coughing fit? Would my voice squeak or wobble?

"I didn’t cast a glance at Catherine and William, not wanting to exchange smiles with them in case I erupted into nervous giggles," he adds. "I wanted to do them both proud."