The Backstreet Boys on fame, friendships and families

The Backstreet Boys have been together for more than 20 years, sold 130 million records, going gold and platinum in 46 countries, and have a star on Hollywood's Walk of Fame.

Now they have a put together a documentary about their careers - called Show 'Em What You're Made Of.

They spoke to the BBC's Tim Wilcox about their music and the secret of being successful for 20 years. They also gave an impromptu performance in the studio.