Johnny Knoxville and Tony Shalhoub will be lending their voices to Teenage Mutant Ninja Turtles, according to Deadline. Knoxville, known for Jackass and Bad Grandpa, has been cast in the role of the Turtle's katana-wielding leader, Leonardo. Shalhoub, the former star of Monk, has been cast as the Turtles' mentor and father figure, Master Splinter. During filming, Leonardo was played by Pete Ploszek and Splinter was played by Danny Woodurn, but Paramount was always clear that recasting voices was an option. In Teenage Mutant Ninja Turtles, from their home in the storm sewers of Manhattan, four Ninjitsu-trained turtles, Leonardo, Raphael, Michelangelo and Donatello and their sensei, Master Splinter, battle evil. Teenage Mutant Ninja Turtles comes to theaters August 8, 2014.