I took a class with a voice coach who worked with Princess Diana and found it was far more challenging than I expected

• I had a voice-coaching session with Stewart Pearce, who worked with Princess Diana.
• I tried breathing techniques used by Diana and Margaret Thatcher to make my voice sound "full."
• The goal, to "turn breath into sound," was more challenging than I expected.

"Hello! Oh - you sound very young," one royal said to me before a phone interview earlier this year.

As Insider's royals reporter, speaking to princes and princesses from around the world no longer phases me. But I was taken aback by this remark.

I understood that it wasn't meant as an insult. But as someone whose voice is essential to their job, I wondered if there was a way to present myself in a more mature or confident manner.

So, I consulted voice coach Stewart Pearce, whose clients included Princess Diana and the former British Prime Minister Margaret Thatcher.

Pearce worked in secret with Thatcher in the 1980s, as the politician "felt that she spoke too fast and that her voice was too shrill," The Times of London reports. After around four or five sessions, the impact on Thatcher was "instantaneous," Pearce told the publication.

He went on to work with Princess Diana in 1995, who requested Pearce's help after watching her BBC "Panorama" interview and feeling "submissive" on screen, he previously told Town and Country.

Reading about Diana and Thatcher's experiences reassured me that I wasn't alone in my struggles.

Breathing exercises Diana and Thatcher used were trickier than I expected

Pearce holds private lessons at his apartment in Chelsea, London, which is where I met him for our session. Upon arrival, I was ushered to a dimly lit room clad with crystals, candles, and a Buddha statue.

The coach "doesn't publish fees as he has such a range of clientele," his personal assistant informed me via email after the session, which was provided in exchange for a review. Booking information can be found on Pearce's website.

After recounting my latest royal interview and telling Pearce what I wanted from the session, I was instructed to sit on a chair in the middle of a room, inhale to the count of 10, then exhale making an "S" sound while Pearce held my rib cage.

The purpose, Pearce said, was to "turn the breath into sound" which he said would make my tone sound more full and subsequently less youthful.

"You are very subtle with your breath, even though it gives you life. It was the first independent action you achieved as you shot out of your mother's birth canal," he said, mimicking the sound of a crying baby. "And it's the last thing you do before you pass. In between, we ignore it."

Because Pearce transitioned so easily between the comedic and serious sides of himself, I had no idea whether it was appropriate to laugh or keep a straight face at that moment. I opted for the latter.

As the session went on, I realized I wasn't good at controlling my breath. I'd recently started weekly meditation and wrongly assumed that Pearce's exercise would come naturally.

At one point, he said: "It's more simple than you're making it - it's not rocket science. It's just breathing."

Other exercises included exhaling and humming, and then using the breath in the exhale to count to the number 12. After each exercise, I was instructed to say: "Hello, my name is Mikhaila," and Pearce would give feedback on whether my tone sounded full.

I would have liked if we had focused more on speech, perhaps with a mock interview or reading exercise. That said, I knew I wouldn't get results overnight. Pearce recommends that clients work on the same exercises for four weeks before reflecting on the progress made.

It's been almost four weeks since my session with Pearce, and in that time I've conducted two royal interviews. And while I'm yet to receive any feedback from interviewees about my voice - and I sometimes had to remind myself to pay attention to my breath - I did notice small differences in my tone.

Pearce's methods aren't for everyone, but I'd recommend him to those who are persistent and patient.

And though I found the class more challenging than I expected, how could I possibly be surprised? Diana and Thatcher didn't conquer public speaking after one session. Perhaps there is still hope for me yet.