Out-of-character moment for comedian after one too many

There is one moment in Jackass Presents: Bad Grandpa when Johnny Knoxville, heavily disguised as an octogenarian to fool the unsuspecting, fell out of character.

To transform into 86-year-old Irving Zisman, Knoxville spent three hours in the makeup chair, and two more if he had to wear a fake chest and back.

The out-of-character moment came in a set-up at a male strip club.

"In that scene I did fall out of character because I'd been there drinking for an hour before the dancers went on and by the time I did my little dance on the red carpet in the club, I was no longer an 86-year-old man. I was a drunk Johnny Knoxville in makeup, chasing everyone like I was Godzilla."

Unlike the previous Jackass films, Bad Grandpa has a loose story as it follows Irving and his 8-year-old grandson (Jackson Nicoll) on a prank-filled road trip.

Some of those pranks have Knoxville very close to being decked by unsuspecting members of the public, who are all filmed using hidden cameras.

But Knoxville says he was never worried.

So far the film has raked in more than US$80 million ($97 million) worldwide.

As for his young co-star, Knoxville appeared with Nicoll in the 2012 movie Fun Size and "instantly fell in love with him".

"He just said the worst things to me and hit me in the zipper constantly ... I love him".

Movie preview
Bad Grandpa starring Johnny Knoxville of Jackass fame
When: At cinemas from tomorrow