The author of the bestselling children's book, The Gruffalo, was taught history by Joan Olivier, during her final years at Camden school for girls, in north London.
"She was definitely one of the more memorable teachers," Ms Donaldson said.
"She had very big eyes behind big spectacles, and used little Scottish words. She called children 'moppets'. "She just seemed like this eccentric, Jean Brodie-ish teacher."
Her recollection of Mrs Olivier's view of 17th-century French history:
"It's a very boring war, no spectacular battles. It's just two ships scraping sides and shouting 'Yah boo' at each other. Don't imagine blazing guns or anything. Five hundred and thirty died of bad food and bad beer.
That's pathetic. There's no bloodshed or anything."
She did not consider her young history teacher a feminist revolutionary, though.
"She wasn't feminist in a burning-of-bras way. She remembered the linen suits and handbags people had," she said.
"I just remember her talking about husbands and children."
Ms Donaldson, who left the school in 1967, says Mrs Olivier encouraged her literary ambitions, inspiring her to research the life of Katherine Aubigny, a civil-war royalist.