Another classmate at her new prestigious school, Marlborough College in Wiltshire, revealed that Kate had “very little confidence”.
“Apparently she had been bullied very badly and she certainly looked thin and pale,” Ms Williamson told the Daily Mail.
Kate’s tutor Joan Gall, also revealed that the royal was very reserved when she joined the school.
“When she arrived she was very quiet. Coming into a big school like Marlborough was difficult, but she settled in quickly,” Ms Gall said.
“It was like a big, happy family. We would do things like bake cakes and watch videos.”
Kate, her husband and brother-in-law Prince Harry, have been vocal in their quest to remove the stigma around mental health. The trio have acted as ambassadors and spokespeople for a variety of mental health-focused charities.
Kate and Prince William - who wed in 2011 - also asked wedding guests to donate to charity Beatbullying.