He revealed his raw emotions about his mother, Princess Diana, who died in a car crash 20 years ago this August.
The magazine's photo was taken by world renowned photographer Norman Jean Roy, who is known for his portraits of celebrities, socialites and high-profile personalities.
Body language and speech expert, Dr Louise Mahler, told News Corp Australia that the photograph was "dead sexy" and it portrayed Prince William as "a woman's man".
"He's not going for a royal look. He's in casual clothing and it's dead sexy," she said.
"While he's not breaking any royal protocols, he is going for a look that makes him look very casual, appealing and approachable.
"The headline too 'A Prince In His Prime' is rather suggestive, there's a bit of innuendo there.
"He is married, but we can't see his wedding band either, so I think he's going to be appealing to the ladies who will see he's giving them the eye."
Dr Mahler said she first noticed that while his mouth was closed, his jaw was released.
"A closed jaw suggests defensiveness. Here he shows open-mindedness and he is ready to engage."
She said his slightly lifted cheeks and half smile were also important factors.
"The half smile releases tension in the back of the throat. It shows he is ready to speak," she added.
As for his hands, Dr Mahler said they were not shielding his body, indicating he is "approachable".
"He does not have clenched fists, his hands are also loose which shows warmth. There is no defensiveness," she said.
"His elbows are released as well and not tight which means he is breathing. Tight elbows suggest protection."
The fact he is leaning slightly forward also suggests he is "welcoming".
"Leaning forward towards the camera means he wants to engage with people and the camera," she said.
As for his collar, which is partly lifting up on his right side, Dr Mahler said it suggests a sense of vulnerability.
"They've done it on purpose, but it is an imperfection, it does suggest some vulnerability," she said.
"Choosing to wear blue still makes him a man, it's a man's colour, but it's masculine without being aggressive."
As for the black and white photograph of Prince William and Kate in the garden with their children, Princess Charlotte and Prince George, Dr Mahler said it portrayed them both in "a complete moment of joy".
"Both of their mouths are open and jaws released, their hands aren't clenched and bodies are unshielded. These are all good symbols," she said.
"They're the kind of people you want to ask to come over for dinner."
