Secret card reveals Princess Diana's cheeky sense of humour

A birthday card that was sent as a joke by Princess Diana to her accountant has come up in an auction house, revealing Diana’s naughty sense of humour.

The card surfaced on an American auction site by the name of Julien’s Auctions after its owner decided that it was time to sell.

According to the seller, the card was sent to Anthony Burrage, her accountant and friend before her tragic death in 1997.

The cover of the card shows Sleeping Beauty with the words: "A little prick in the hand sent Sleeping Beauty to sleep".

Once the card is opened up, the punch is revealed: "Only the big ones are worth staying awake for!"

It is addressed to Tony and says: "A belated Happy Birthday for the 5th! From Diana."

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Experts are predicting that the card could fetch as much as $1,200 - $1,750 (£600- £900), but right now the bidding currently sits at $375 (£192) in the online auction.

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When speaking to the Mirror, the anonymous owner said: "I know that Diana liked to send humorous cards, but I haven't seen any quite this naughty, so for me it really shows that she was a fun human being that could share some dirty jokes with her closest friends.

"This is a secret card that has been kept hidden for many years. A true gem for anyone that is a fan of this special human being."

Would you consider buying the card?