Johnny Knoxville and Naomi Nelson
04/18/2011 AT 01:00 PM EDT
Johnny Knoxville is expanding his family with a third child.
Naomi and I are super happy to announce that we are having another little bambino in the fall," the Jackass
star, 40, wrote on his Facebook page
"My 15-year-old daughter Madison is very excited about it, and her 16-month-old little brother
Rocko has, well, no clue. Wahoo!!"
Knoxville – whose latest film, Jackass 3.5
, is currently streaming online – tells the Toronto Sun
that his brand of gross-out humor isn't meant to be taken all that seriously.
"People want to turn their brain off and go to the movies and laugh," he says. "There isn't any deeper meaning there. If you wanted to laugh and you did at our movie, then good."