Emma Stone - Stars Unite To Honour Teen Heroes30 October 2012
Emma Stone, Josh Duhamel, Justin Bieber and Tyra Banks are teaming up to honour teenagers who have dedicated themselves to improving the lives of others.
Each star will pay tribute to volunteers at the fourth annual Nickelodeon TeenNick HALO Awards, handing out prizes to youngsters who spend time "helping and leading others".
Nick Cannon, who is married to Mariah Carey, created the awards show and will serve as its host at the Hollywood Palladium ceremony next month (Nov12).
The four honourees will each receive $10,000 (£6,250) to further their education and a donation to either their own charity or a charity of their choice.