Prince Henry of Wales has often been known as the bad boy of the British royal family. Unlike older brother Prince William, who recently welcomed his second child with Kate Middleton, Harry is single and likely up to his usual mischief on his 31st birthday.

Born in London Sept. 15, 1984, to Prince Charles and Princesss Diana, Harry was 12 when his mother died in a car crash in Paris. He has always maintained a close relationship with his family. "Conversations with my mother, father, my grandparents, as I've grown up have obviously driven me towards wanting to try and make a difference as much as possible," he said.

Princess Diana Will Harry Princess Diana, with Prince Charles behind her, is seen with sons Prince William and Prince Harry (front) during a photo session in Spain, Aug. 9, 1987. Photo: Reuters

Harry made a name for himself as the wild child of the pair of princes, often photographed coming out of pubs drunk or dating various models, and in one particularly memorable moment, playing billiards completely nude. He also was once lambasted for dressing as a Nazi at a costume party.

In his professional life, Harry has been much more austere and after developing an interest in the military at a young age, he eventually joined the Household Cavalry as a second lieutenant, serving in Afghanistan for two months. He also holds honorary appointments in the Royal Navy and Royal Air Force. The Prince reportedly will be looking at vintage airplanes with World War II veterans as part of his birthday activities.

Prince Harry Britain's Prince Harry leaves after a flyover of military aircraft, following the Afghanistan service of commemoration at St. Paul's Cathedral in London, March 13, 2015. Photo: Reuters/Stefan Wermuth

Harry has served as a cultural ambassador to the U.K., often representing the royal family at social events, and meeting the likes of Lady Gaga or having tea with U.S. first lady Michelle Obama at his family home in Buckingham Palace.

Michelle Obama Prince Harry U.S. first lady Michelle Obama meets Prince Harry at Kensington Palace in London, June 16, 2015. Photo: Getty Images

[9:16] Britain's Prince Harry (L) stands with performers Lady Gaga and Tony Bennett before a Well Child charity concert at the Royal Albert Hall Britain's Prince Harry stands with American singers Lady Gaga and Tony Bennett before a WellChild charity concert at Royal Albert Hall in London, June 8, 2015. Photo: Reuters/Alan Davidson/pool

Harry is reportedly close with his brother William as well as his sister-in-law, Princess Kate, and their children Prince George and Princess Charlotte. The prince collaborated with Kate's sister, Pippa Middleton, on a children's book about the youngest additions to the royal family, entitled "Hooray! It's a New Royal Baby!" 

Often stating his desire to have a family of his own, Harry once said, "I've longed for kids since I was very, very young," adding, "I'm waiting to find the right person, someone who's willing to take on the job."

Prince Harry Britain's Queen Elizabeth, Prince Philip, Prince Harry, Catherine, the Duchess of Cambridge, and Prince William, the Duke of Cambridge, watch a flyover from the balcony of Buckingham Palace in the annual Trooping the Color ceremony, June 14, 2014. Photo: Reuters