Psy, Drake, Gotye join American Music Awards birthday bash

South Korean singer PSY poses with his Best Video award backstage during the MTV European Music Awards 2012 show at the Festhalle in FrankfurtLOS ANGELES (Reuters) – The American Music Awards rings in its 40th year on Sunday, with top nominees like Rihanna and Nicki Minaj battling for the top trophies and Stevie Wonder leading a tribute to the show's late founder, Dick Clark. Variety is the key to this year's three-hour ceremony from Los Angeles, with performers including Canadian pop star Justin Bieber, 1990s ska-punk band No Doubt, alt-rockers Linkin Park, country-pop darling Taylor Swift, Korean Internet sensation Psy and British-Irish boyband The Wanted. …