'Just don't get caught' Princess Diana's cheeky warning to son Prince Harry has been revealed

• Princess Diana is said to have given son Harry some cheeky words of wisdom when he was younger, telling him, 'Just don't get caught'.
• The Duke of Sussex was just 12 years old when his mother died.
• He has since grown up to be known as the "cheeky one" according to new book, as it's revealed Prince Harry is set to star in a new Netflix documentary as he talks about returning from “darkest place”

Princess Diana previously encouraged her son Harry to show his rebellious side after reportedly telling him, 'You can be naughty. Just don't get caught.'

The words of wisdom come to light in the new Harry and Meghan biography Finding Freedom, written by Omid Scobie and Carolyn Durand.

READ MORE: Prince Harry is set to star in a new Netflix documentary as he talks about returning from “darkest place”

The authors claimed Harry to the Princess of Wales' "message to heart" and suggest it is what has spurred on his desire to establish himself as "the cheeky one".

Harry, who is married to wife Meghan and has one-year-old son Archie, is known for sticking his tongue out during Trooping of the Colour.

It's also revealed Diana used to carry out cheeky things herself like smuggling Starburst into her son's, Prince William and Harry's socks when she would visit them at boarding school to watch them play football.

READ MORE: Royal A Levels: How Prince William, Harry and Kate did in their exams

The authors wrote, 'It seems he took to hear the first part of his mother’s message about getting into trouble, but couldn’t quite figure out how to pull off the second part about not getting caught.'

As he was once caught having left Kensington Palace and wandered onto Kensington High Street only to call his mother's royal protection officer Ken Wharfe, on the walkie talkie to advise him of his mission accomplished.

Even as a teenager, Harry was caught with cannabis and was sent to a drugs rehabilitation clinic for a day.

According to News of the World, at the time the 17-year-old had smoked cannabis on the grounds of his Highgrove Home, and drunk heavily at a local pub.