Nick Jonas: 21 Under 21 (2012)
Nick Jonas: 21 Under 21 (2012)

No. 10: Nick Jonas

Last Year's Rank: 8

Birthdate: September 16, 1992 (Age 20)

Why He's Hot: Nick Jonas spent the beginning of 2012 on Broadway, where he replaced Daniel Radcliffe as J. Pierrepont Finch in "How to Succeed in Business Without Really Trying." Since then, the youngest Jonas Brother has reunited with his siblings, and the trio is back in the studio,making new music and preparing to go back on tour. His 2010 solo album, "Who I Am," debuted at No. 3 on the Billboard 200, but as Nick told the world in his brother Kevin's E! reality show, "Married to Jonas," he's ready to bring back the band that made all three JoBros famous. The brothers have a sold-out Oct. 11 show at NYC's Radio City Music Hall, and atour has been teased to follow. The new album could be out by the end of the year, as the JoBros have been using the hashtag #JB2012 to promote it.

Video Below: Nick Jonas sings "I Believe In You" on Live With Kelly

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