R&B singer and producer Pharrell Williams was in his element at the iTunes Festival in London this week, and thanked his fans for making his song "Happy" from the movie "Despicable Me 2" the most downloaded tune in Great Britain. Williams is a multiple Grammy award winner as a producer and songwriter, but 2013 was the year that thrust him into the limelight as a solo artist. In addition to "Happy", he co-wrote and featured on international smash hits "Get Lucky" with Daft Punk and "Blurred Lines" with Robin Thicke.