It's been two years since Rovio's Angry Birds first rocked the Apple App Store with its bird-flinging, pig-squashing antics, and to show their appreciation for their fans continued support, Rovio have launched a special Happy Birthday update for the app. The update adds new birthday cake-themed levels, as well as a handful of new achievements.

Since its launch in December 2009, Angry Birds has racked up over 500 million downloads around the globe, making it the most popular mobile game in history.

Fans of the game not content with just receiving new downloadable content can join the Angry Birds in person at Forbidden Planet stores today in the UK, where there will be special lines of Angry Birds merchandise on sale and - if you're quick - cake. Not sure what all the fuss is about? Read our review of Angry Birds here.

Source: Recombu