"She was a lovely person, but she kept herself to herself," Khoo said in an interview with Woman magazine.
Let's hope Kate puts the £1,600 two-week course to good use in her two newly renovated homes. According to Metro, the royal couple's Kensington Palace apartment has been kitted out with a £15,000 Sub-Zero & Wolf fridge freezer and a £8,000 Wolf oven.
However, Khoo also confirmed Kate missed a couple of classes when she wasn't well.
"Kate was ill for a few days, so I took notes for her," Khoo said. Could that have been morning-sickness?
WATCH! Kate's also been taking cooking tips from her Italian housekeeper...
Cooking is not the only thing Kate has been up to lately. See all the highlights from the Royal Tour of Australia and New Zealand below: