Ed Sheeran should be very happy for having hit number one. "Sing" - produced by and featuring Pharrell Williams, the "Happy" singer - is Sheeran's first number one single in the UK, his home country, and the US. The successful hit is the third track on X (pronounced as "multiply"), his sophomore album, which has also become the UK's fastest selling album this year. The chart-topper also proves that the young musician can rap and has a sweet falsetto voice.