The fourth season of America"s Got Talent, an American television reality show talent competition, premiered on the NBC network on June 23, 2009. Country singer Kevin Skinner was named the winner on September 16, 2009. This season is the first season to be broadcast in high definition.    This season"s host was Nick Cannon, who replaced Jerry Springer. Springer had said that he could not host due to other commitments. All Season 3 judges returned for the fourth season, despite rumors that Sharon Osbourne would be leaving the show.    Season 4 was David Hasselhoff"s final season as a judge. This season started broadcasting LIVE on August 4, 2009.