Former X Factor contestants One Direction rounded off a successful year of US invasion after being named top new artist and Maroon 5 were top group.

BBC: Adele named Billboard top artist of 2012

He won the Country Music Association's best new artist in November, was tied with Swift as the top-nominated country artist at Sunday's Grammy Awards, where he performed, and now takes center stage in Las Vegas.

NPR: Eric Church Leads ACM Awards Nominations With 7

That album generated three Top 20 hits and helped Hornsby win the Best New Artist Grammy, and it laid the groundwork for a wildly diverse career encompassing jazz, pop, classical, bluegrass, folk, rock and Vaudeville.

NPR: Bruce Hornsby: From Jazz to Folk to Rock