'I'M THE KING OF THE WORLD!'That was the cry from Leonardo DiCaprio as he stood astride the bow in Titanic - the movie that would go on to smash all records,raking in a whopping ?1.1 billion worldwide.Now, few Hollywood movers and shakers would dispute that statement as Leo has rocketed to become one of the highest paid actors in the world.And his position looks set to be secure after an incredible 2013 which saw Hollywood's hottest talent appearing as the eponymous Jay Gatsby in The Great Gatsby, following swiftly on the heels of the great success of Quentin Tarantino's blockbuster Django Unchained.It's a far cry from the heart-throb's humble beginnings - scraping for parts in TV commercials and soap operas before catching the eye in Baz Luhrmann's stylish Romeo + Juliet and then achieving worldwide superstardom with Titanic.He cemented his reputation with captivating performances in films like Catch Me If You Can, The Departed, Inception and The Aviator, for which DiCaprio won a Golden Globe.Yet, although he's spent over 15 years at the top of his profession, Leonardo remains something of an enigma - his often daring movie choices suggest an actor still striving for perfection.Leonardo: The Biography charts DiCaprio's meteoric rise to fame and delves beneath his polished Hollywood image to examine just what makes him tick.