Tightrope daredevil Nik Wallenda is preparing for his greatest challenge yet, a walk across Niagara Falls.

At a press conference before attempting the stunt, the 33-year-old revealed he first came up with the idea for the challenge 27 years ago.

He said: "At the age of six is the first time I visited the Falls with my parents and my sister, and that was when the vision came to me to walk across Niagara Falls."

He will attempt to walk across the Horseshoe Falls, one of the two massive waterfalls which makes up Niagara Falls between the United States and Canada, at 10pm on Friday night, local time.

Wallenda will uncharacteristically be wearing a safety harness, something he has never worn before, because the stunt is being broadcast live on television.

He insist the harness will not make the challenge any easier: "It doesn't keep me on the wire in any way, it keeps me safe from dying.

"I still have to balance, I still have to stay on top of that wire."