Camilla, the Duchess of Cornwall, is a royal granny with an amazing sense of humour.

Duchess Camilla might have failed in her attempt to make a joke about coronavirus on Wednesday, but the next day, she pulled out her best puns for an interaction with children on the occasion of World Book Day.

Sharing her love for reading with the students of Bousfield Primary School in London on Thursday, the duchess joked about how she becomes a "Gangsta Granny" who plots to steal the Crown Jewels, in a reference to David Walliams' popular comedy fiction novel for children "Gangsta Granny," reports Hello.

"Books can take you anywhere – a bit like stepping into your very own Tardis. You can play Quidditch with Harry Potter, win the golden ticket to Charlie's Chocolate Factory, go on a secret mission with Alex Rider, or, if you are like me, become a Gangsta Granny and plot to steal the Crown Jewels," the 72-year-old quipped.

“If can give you one piece of advice, it is to put down your phones and pick up a book, especially before you go to bed. Books never lose their signal or run out of battery and they will always take you to a thousand different worlds with every turn of a page.” #WorldBookDay 📚 pic.twitter.com/ZIHUpgNRkS

— Clarence House (@ClarenceHouse) March 5, 2020

"Gangsta Granny" tells the story of a child Ben and his grandmother, who appears boring at first, but later turns out to be an international jewel thief who wants her grandson's help in her conspiracy to steal the crown jewels.

Camilla also urged the young children to replace their cellphones with books, saying: "If I can give you one piece of advice before I leave, it is to put down your phones and pick up a book, especially before you go to bed."

"After all, books never lose their signal or run out of battery and they will always take you to a thousand different worlds with every turn of a page. We all need to read for at least 10 minutes a day. It is such a magical thing to do and it will help you in every possible way – even with your maths and science," the Duchess of Cornwall added.

For her day out with the children, the royal opted for a black midi skirt, pairing it with a tailored navy blue zip-up jacket and her favourite pairs of knee-high boots. It was a solo royal engagement for Camilla, who visited the London Transport Museum with husband Prince Charles on Wednesday to celebrate 20 years of Transport for London (TfL).

Charles and Camilla
Camilla, Duchess of Cornwall visits St Christopher School on day 3 of a Royal tour of the United Arab Emirates in Manama, Bahrain. P John Stillwell/ Getty Images

During the visit, the duchess had made a joke about coronavirus, which has recently witnessed a rise in cases in the UK. While stepping into an old air-raid shelter, Camilla had quipped: "I'm self-isolating."