Kermit's Swamp Years (2002)
Kermit's Swamp Years is a 2002 direct-to-video film, directed by David Gumpel, featuring Jim Henson's Muppets, including a 12-year-old Kermit and best friends Goggles and Croaker, who travel outside their homes in the swamps of the Deep South to do something extraordinary with their lives. The film, which tells the story of Kermit the Frog's early life, is a prequel to The Muppet Movie. As of 2002, this is the last Muppet film to receive a G rating from the MPAA, as a few later Muppet films, starting with the TV Christmas film It's a Very Merry Muppet Christmas Movie, which aired in the same year, have received a PG rating from the MPAA. This is the first Muppet movie that does not feature the Muppets, expect: Kermit the Frog, Statler and Waldorf & Foo-Foo
More at Wikipedia.