Princess Michael of Kent refused to eat a Chelsea bun - while judging the World Chelsea Bun Awards.
The royal, 78, who is married to Prince Michael of Kent, a first cousin of the late Queen, stepped in to help out at the awards in Partridges, an upmarket shop in Piccadilly who supply groceries to the Royal Family.
Princess Michael's daughter-in-law, actress Lady Sophie Winkleman - was supposed to be judging the awards but had a diary conflict and asked her mother-in-law to step in.
But royal wires appeared to get crossed, with Princess Michael unaware she would have to eat anything while judging a baking competition.
'I wasn't told by my daughter-in-law that I was going to do a taste.
Because I'm not going to taste,' she said on Channel 5's The Royal Borough: Kensington & Chelsea which airs tonight.
'When she said "help me out with is wonderful children's charity" she didn't say I had to taste.
Image conscious Princess Michael has kept trim well into her eighth decade and has previously said she avoids food with cream or salt.
Princess Michael of Kent refused to try a Chelsea bun - while judging the World Chelsea Bun Awards.
Pictured with John Shephard, the managing director of the shop
Speaking to the Guardian in 2007, she prefers English food to French because she is 'very health conscious' and French food has 'too much cream'.
But she added there is 'too much salt and pepper' in British cuisine, but she like it because it is 'plain and not bland'.
'You are not aware of much oil in the cooking, nor too much in the way of herbs - again a foreign thing, other than English herbs like rosemary,' she said.
The royal added that if she skips lunch she 'eats jelly' because it is 'filling and domino4d not fattening' but a typical lunch for her would be 'a delicious salad with lots of yummy things in it and a dressing made out of tahini and goat's yoghurt'.
In the show, Princess Michael decided to judge the buns by eyesight only - before observing how the other judges, including Patridge's managing director John Shephard, had a lot to eat.
'I supposed the judges have to have a jolly good bite of each bun,' she added.
'I must say the look of them is just splendid, my expert eye goes straight to the biggest thing, they are beautiful,' she went on.
The royal, 78, who is married to Prince Micheal of Kent, a first cousin of the late Queen, stepped in to help out at the awards in Partridges, who supply groceries to the royal family
Princess Michael's daughter-in-law, actress Lady Sophie Winkleman (pictured with Queen Camilla) wasn't able to attend the event
She noted that the pomegranate buns were 'attractive' and the savoury buns were 'very interesting'.
'It's so large, it's almost a meal,' she added about another bun, before observing it was 'very, very, hard to judge'.
Partridges are a St James' based, family-run grocer that became a favourite of the Queen.