Prince William reveals how his poor eyesight helped with nerves when public speaking

 Prince William is trying to get men to open up about their mental health, and for a new documentary on the issue he revealed his own unorthodox way of managing his nerves.

Speaking ahead of a BBC show on men's mental health and football, the prince offered his own unconventional way of dealing with public speaking anxiety -- by not wearing contact lenses.

In a preview from the documentary "Football, Prince William and Our Mental Health," which will air Thursday in the UK, an interviewer asked the prince: "I wonder if you suffered anxiety, obviously because you've got people looking at you 24/7?"

"Certain days, especially certain speeches as well, when I was growing up, you definitely get a bit of anxiety about it," William explained, adding that he felt a need to "get it right" and that he was aware of certain people watching him speak.

"Weirdly the sort of thing that helped me which I didn't actually realize at the time, was... my eyesight started to sort of tail off a little bit when I got older and I didn't used to wear contacts when I was working.

"So actually when I gave speeches, I couldn't see anyone's face," he said. "And it helps, because it's just a blur of faces."

The prince, who said he wears contact lenses now, told the interviewer that at the time he could see the paper in front of him but not the whole room.

"Actually that really helped with my anxiety," he said.

The documentary, which will air Thursday evening in the UK, follows William's campaign to engage British men in the issue of mental health, using football as a way of getting them talking and breaking taboo.

In the same documentary, William spoke to soccer player Marvin Sordell about the death of his mother, Diana, as part of a discussion about how becoming a parent can lead to the resurfacing of feelings from a traumatic event.

Last year, the Duke of Cambridge opened up in a BBC documentary about the loss of his mother, Princess Diana, saying he felt "pain like no other" after her death in a car crash in 1997 when he was 15 years old.

He also said British people -- particularly men -- should feel comfortable talking about mental health issues.