Lady Gaga defies definition. She's a singer, a songwriter, a burlesque dancer and dresser, a performance-artist, a fashion designer, a sex symbol, a chart-topping pop star... The list goes on and it will never capture the unique musical and entertainment talent that is Stefani Joanne Germanotta, AKA Lady Gaga.

Late in 2008 she emerged from mainstream obscurity to become, almost overnight, one of the world's most recognisable and listened-to women, with a hybrid album The Fame/Fame Monster and a sequence of huge hits like 'Just Dance', 'Poker Face', 'Paparazzi' and 'Bad Romance'. Lady Gaga is a phenomenon and, like her or love her, you can't ignore her.