It's learned that separate actors will be voicing the characters in Teenage Mutant Ninja Turtles - at least for Leonardo and Splinter - as Johnny Knoxville and Tony Shalhoub have been added to the cast.
Deadline reports that Johnny Knoxville will voice Leonardo, and that Tony Shalhoub will voice Splinter.
Regarding the actors that physically portrayed the characters, it's reported that they were only guaranteed a physical role with Paramount apparently always leaving the possibility open to bring in voice actors.
Pete Ploszek plays the role of Leonardo for filming, while Danny Woodburn played Splinter.
Johnny Knoxville is no stranger to voice acting have played Johnny Krill in SpongeBob SquarePants as well as Hoyt Platter in King of the Hill.
Tony Shalhoub, known for the Monk TV series, had voice acting roles as well with Luigi in Cars.
"Teenage Mutant Ninja Turtles" has an August 8, 2014 release directed by Jonathan Liebesman, produced by Michael Bay starring Megan Fox as April O'Neil, William Fichtner as Shredder, Pete Ploszek as Leonardo, Alan Ritchson as Raphael, Jeremy Howard as Donatello, Noel Fisher as Michelangelo, Will Arnett as Vernon Fenwick, and Whoopi Goldberg as Bernadette Thompson.
The city needs heroes. Darkness has settled over New York City as Shredder and his evil Foot Clan have an iron grip on everything from the police to the politicians. The future is grim until four unlikely outcast brothers rise from the sewers and discover their destiny as Teenage Mutant Ninja Turtles. The Turtles must work with fearless reporter April and her wise-cracking cameraman Vern Fenwick to save the city and unravel Shredder’s diabolical plan.