Johnny Knoxville and his wife Naomi Nelson are expecting their second child.

The 'Jackass' star - who already has 15-year-old daughter Madison from his ex-wife Melanie Clapp - is "super happy" about the forthcoming baby, who will be a brother or sister to their first child, 16-month-old Rocko.

He wrote on Facebook: "my wife naomi and i are super happy to announce that we are having another little bambino in The Fall. my 15-year-old daughter madison is very excited about it, and her 16-month-old Little Brother rocko has, well, no clue. wahoo!!(sic)"

Johnny - whose real name is Philip John Clapp - previously revealed he "hoped" he was a good parent but had to rethink his approach when he once found himself "ordered to the ground" by police when he was babysitting Madison.

The 40-year-old actor said: "I hope I'm a good father. Sometimes I get excited and things happen and I'm trying to do good.

"I was babysitting my daughter and her friends, they were all at the house one day I set up the backyard as a Shooting Gallery with helium balloons and whatnot and we were having fun shooting the helium balloons when the cops burst in and ordered me down to the ground with guns.

"(Cops) came in my house! Apparently someone said there were shots fired in the neighbourhood."