The network said it has already taped the sit-down, which CNN is touting as William's first extensive television interview since his wife, Kate, gave birth to their first child, Prince George, last month.
"Big royal interviews don't happen overnight and if you're lucky, they come through and at just the right time. For a long while, I have wanted to speak to Prince William about the cause closest to his heart, African conservation, and I've been in contact with his office for more than two years about making it happen," CNN's Max Foster said.
"Of course, I had to ask him about becoming a dad for the first time as well. I think you will be struck by how natural he is, passionate, frank and happy. So many parents will relate to what he's saying. William isn't just a big star, he is set to become head of state in 16 countries and here he is talking about his own successor for the very first time. It's an historic moment and I am thrilled he agreed to speak to me."
The program is to premiere on CNN and CNN International Sept. 15.