As his brother and sister-in-law prepare to become parents, Hello! Online takes a look at the role Uncle Harry will play in the royal baby's life.
Unsurprisingly given his rapport with children, Harry has previously spoke of his own desire to be a father.
"I've longed for kids since I was very, very young," the royal said in May 2012. "So I'm waiting to find the right person, someone who's willing to take on the job."
This longing was clear when the 28-year-old was seen playing with a baby at an event for veteran servicemen in Colorado during his tour to the USA earlier this year. Harry took a real liking to one youngster, Sebastian Wilksowski, much to the delight of his mother, Julia.
"Who is this little guy?" asked the Prince, adding, "you have a lot of hair for a ten-month-old."
The soon-to-be uncle proved a big hit with Sebastian and his family by being so playful with the baby.
"He made silly faces and then he started blushing a little bit because he didn't think Sebastian would grab him," said Julia. "Then Harry went to walk away and came back with another funny face. It was cute."
"He is wonderful with children," added Sebastian's father Kip, a 43-year-old retired air force pilot.
"We suspect Harry will make a caring and thoughtful uncle with natural instincts to be the naughty influence in the baby's life," said Julia. "It was just so cool, very genuine. I think he'll make a great uncle."
Those royal family church services will be easier for Baby Cambridge to handle with Harry on hand to give a sly wink or poke out his tongue. When he or she wants to play outside or learn to ride William and Kate need look no further than sports-mad Uncle Harry, who is happiest in the saddle.
Then again Harry will be there in the tough times too. Having weathered so many storms in his own life, he will be the perfect mentor when it comes to handling the pressures of life in the royal family.
He is at his best with the sick and vulnerable children he meets through his extensive charity work. Like his mother, Princess Diana, the Prince has always fought to help under-privileged children.
In 2006, he founded a charity in Lesotho along with Prince Seeiso, the younger brother of the country's King Letsie in tribute to each of their late mothers. Sentable, which means "forget me not," supports children in Lesotho suffering with HIV and AIDS, as well as those orphaned by the virus or with disabilities.
The British royal visited his project in February and joined the scores of excited children performing traditional dances. During his tour, Harry also visited a school for deaf and blind children where he took the time to speak to some of the youngsters.
"What do you want to be when you grow up?" Harry asked one young boy, and on hearing response to be "a soldier," the Prince said, "I'm a soldier myself. I'll tell you what that's like next time."
Photos: Getty Images
A version of this article was published at hellomagazine.com with the headline "What kind of uncle will Prince Harry be?"