DreamWorks Animation knows how to get their hands on some of the biggest stars out there. Just look at the cast they're starting to conjure up for their new animated movie 'Happy Smekday!' The animation company just got their lead voice actors, and you RiRi and 'Big Bang Theory' fans should be happy.

The Hollywood Reporter just announced that 'The Big Bang Theory' star Jim Parsons and singer/actress Rihanna will be lending their voices to the latest DreamWorks Animation project. 'Happy Smekday!' is based off the book called 'The True Meaning of Smekday' by Adam Rex. Tim Johnson ('Over the Hedge') will be directing the comical animated feature off the script written by Matt Ember and Tom J. Astle. These are the same two writers who not only put together the script for 'Get Smart' but are also writing 'Me and My Shadow' for DreamWorks Animation.

In 'Happy Smekday!' we follow a friendly alien race who invades the Earth in order to hide from their biggest adversary. But one alien (voiced by Parsons) accidentally lets the enemy alien race know their whereabouts. From there he begins his adventure on the run with a teenage girl (voiced by Rihanna) across the post-apocalyptic nation. Now Jim Parsons has previously lent his voice to a couple other animated works, but this will be the first for Rihanna.

'Happy Smekday!' sounds like a really sweet story but it feels like the next couple of years are going to be overflowing with post-apocalyptic pictures. We have Edgar Wright's new movie 'The World's End' then Evan Goldberg and Seth Rogen's comedy 'The End of the World' in 2013 topped off with this in 2014 (and 'Seeking a Friend for the End of the World' in theaters this Friday). Why the sudden fascination with the apocalypse?