The presenter revealed that she sat with her sister, who had previously been sent a secret note from the royal, as the news unfolded.
"My sister was sitting on my parents' bed in tears holding the little note Diana had once written for her when she was having dinner with my dad," she divulged in this week's issue of OK! magazine.
"It said: 'I'm at this grand dinner sitting with your daddy and I'd far rather be in McDonald's with my boys'."
Kirstie, 45, grew up knowing the Princess of Wales due to her father's relationship with the royal and his work on her dress sale.Related articles
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I remember Prince William going around the whole deck kissing everyone goodnight
"I met her and Prince Charles on a boat in Turkey when I was 19," she revealed.
"I remember Prince William going around the whole deck kissing everyone goodnight."