Eagle Strike by Anthony Horowitz

Sir Damian Cray is a philanthropist, peace activist, and the world's most famous pop star. But still it's not enough. He needs more if he is to save the world. Trouble is, only Alex Rider recognizes that it's the world that needs saving from Sir Damian Cray. Underneath the luster of glamour and fame lies a twisted mind, ready to sacrifice the world for his beliefs. But in the past, Alex has always had the backing of the government. This time, he's on his own. Can one teenager convince the world that the most popular man on earth is a madman bent on destruction--before time runs out?