Diana went 'red with embarrassment' when Prince Harry told her joke at school

ok.co.uk:

The Royal Family is famous for exchanging gag gifts at Christmas, but it turns out the festive spirit lasts all year round with their playful banter.The late Diana, Princess of Wales, definitely led the pack when it came to fun and games, often buying cheeky presents or pulling pranks on her boys.

There have been plenty of tales about Diana's playful side, like the time she would give her godchildren the loudest toys just to wind up her pals or when she cheekily arranged for Prince William to be met by three top models.

It seems the princess knew how to cause a stir with her humour. But one story that really stands out is when Diana's youngest son, Prince Harry, was about to innocently share one of her more "risque jokes" with his teacher, a moment captured in Royal author Robert Jobson's book 'William At 40: The Making Of A Modern Monarch'.

Jobson pens the scene vividly, saying, "On the school run one morning, she started telling a risque joke, apparently unconcerned that Harry was drinking in every salacious word.