The creator displayed his latest work over the weekend as he joined the fans at St Mary's Hospital in Paddington eagerly awaiting news of the second royal baby's birth.
Kaya's painting shows the pregnant duchess with her son George, one, on one side and a donkey on the other.
He described Kate as a "21st century saint."
Kaya added to People: "She can't answer back, so the satire is quite soft. I'm not really making fun of the princess, but of the way we all look at her."
Anticipation is building about the second royal baby as it's believed Kate's original due date has come and gone. There have been rumours today that doctors may induce if the baby doesn't come this week.
Kate and William welcomed their son Prince George at the Lindo Wing on 22 July 2013.
It's not yet known whether baby number two is a boy or girl.
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