While Harris' exact character wasn't revealed, it was said that he would play the main live-action character in the film, which will be a CGI/live-action hybrid film.
Filming was said to start in April and the film has been slated for release on July 29, 2011. We'll be sure to keep you posted with any other updates regarding The Smurfs as soon as we have more information.
The Smurfs was released July 29th, 2011 and stars Hank Azaria, Neil Patrick Harris, Jayma Mays, Sofía Vergara, Tim Gunn, Madison McKinley, Meg Phillips, Julie Chang. The film is directed by Raja Gosnell.