Prince William, 26, rocking a full beard in rare clubbing photo with Princess Kate will make you double take

Prince William has been clean-shaven since his twenties, but that hasn't always been the case for the Prince of Wales, who proudly rocked a full beard for a brief moment in 2008.

Most royal fans will have seen the now-famous photograph of a bearded Prince William at Sandringham on Christmas Day in 2008, after it reemerged on social media following the release of Prince Harry's tell-all memoir, Spare.

Prince Harry was the first to sport a beard on his wedding day to Meghan Markle after receiving formal permission from his late grandmother, Queen Elizabeth II.

Writing of the moment his facial hair caused tension with his brother, however, Harry revealed William offered a "bristled" response to his polite request. "Not the done thing, he [William] said. Military rules, so forth."

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Harry wrote that his brother "wouldn't let it go" and that the disagreement continued "in person, on the phone, for more than a week" before William admitted that his grievance with Harry's facial hair was because he wasn't allowed to keep his.

Harry added: "Ah, there it was. After he'd come back from an assignment with Special Forces, Willy was sporting a full beard, and someone told him to be a good boy, run along and shave it. He hated the idea of me enjoying a perk he'd been denied."

Prince William's albeit brief encounter with facial hair in the noughties defines a playful and coming-of-age era of the royal's life. He had only recently graduated from St Andrews University, had rekindled with a young Kate Middleton after their high-profile split, and was just about to serve on attachment to the Royal Air Force.

In unearthed photographs captured from 2008, Prince William and Princess Kate, who was then just the royal's girlfriend, were seen leaving the darkly glamorous Whisky Mist nightclub. William looks almost unrecognisable in the photos as he rocks a full, bushy beard.

Reports at the time reveal that Kate had gone for a dinner date with her sister Pippa Middleton at 'Eight Over Eight' restaurant in Chelsea. Kate then arrived at Whiskey Mist just after midnight for a night of dancing with her boyfriend Prince William.

Given the Prince of Wales' more senior role in the Firm, it seems unlikely we'll ever see him with a beard again - but these photos certainly serve up some noughties nostalgia…