Artist James Brennan has claimed the annual Bald Archy Prize for his work, 'The Official Portrait of the Danish Royal Family', which shows Australian-born Princess Mary breast-feeding daughter Princess Isabella and her husband Prince Frederik drinking beer in his underpants.
The award was created 15 years ago to recognise paintings of "humour, dark satire, comedy or caricature."
Brennan said: "I was vacuuming and it just popped into my head out of nowhere. I saw a magazine probably a couple of weeks before that with Princess Mary and baby Isabella and a family portrait, and the idea just came out of nowhere. I hope they like it.
"I think Mary being Australian, she might have a bit of an rude sense of humour, she might appreciate it.
"They're probably just like everybody else, besides the wealth and the fame. I just wanted to bring them down to our level."
The painting also shows Mary and Frederik's son Prince Christian sitting on a potty picking his nose, while he is watched by a Tasmanian devil.
Brennan - who won a cash prize of $4,600 for the cheeky painting - took advantage of Australia's obsession with Princess Mary, who was a real-estate agent before she met Prince Frederik at the 2000 Olympic Games in Sydney, Australia.
more Zara Phillips set to star in 'Strictly Come Dancing' The 26-year-old royal - Queen Elizabeth's eldest granddaughter - is said to be in talks to appear in the BBC One programme along with rugby star boyfriend Mike Tindall.
Camilla stunned onlookers by going for an impromptu paddle in the sea The royal - who is married to Britain's Prince Charles - rolled up her trousers and took the plunge at Llangranog after taking a break from official engagements to go out walking in the sunshine with a female companion and two detective bodyguards.