A joke birthday card sent by Princess Diana to her accountant has given an insight into the late royal's cheeky sense of humour.
The birthday card, thought to have been sent in the Nineties, has surfaced on LA-based celebrity auction site Julien's Auctions after its anonymous owner decided to sell it, reports the Daily Mail.
According to the anonymous seller it was sent by Diana, who was killed in a car accident in Paris in 1997, to Anthony Burrage, an accountant and friend.
The front of the card features an image of Sleeping Beauty, which reads: "A little prick in the hand sent Sleeping Beauty to sleep".
It's a reference to the fairytale in which Sleeping Beauty falls into a deep sleep after pricking her finger on a spinning wheel, but also a cheeky double entendre that's followed up with the punch line inside the card: "Only the big ones are worth staying awake for!"
The card is addressed to 'Tony' and reads: "A belated Happy Birthday for the 5th! From Diana."
The card is expected to fetch as much as $1,200 - $1,750 (£600- £900), and bidding currently stands at $375 (£192) in the online auction.
The description by the bidding site describes the card as 7 by 5 inches, and reads: "A humorous birthday card with 'Sleeping Beauty' on the cover, handwritten in black felt pen by HRH Princess Diana, "Tony, A belated Happy Birthday for the 5th, from, Diana."
"Tony refers to Anthony Burrage, accountant and trusted employee of HRH Princess Diana."
Speaking to the Mirror, the anonymous owner of the card 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."
MailOnline has contacted Julien's Auctions for further comment.
Diana's former butler Paul Burrell, 60, has previously claimed that the mischievous princess once put a fake dog poo in Prince Harry's Christmas stocking when he was a child.
Speaking to the Mirror last month, Mr Burrell recalled how the now Duke of Sussex, now 33, was thrilled with the gift - and even planned to use it to play a prank on his grandmother the Queen.
He said: "She'd spend hours looking for jokey things for their stockings. One year, Harry got fake dog poo."
Mr Burrell served as a footman to the monarch before working for Diana, and has often told stories of his time in royal circles.