The 24-year-old has signed on as one of the lead voices of the film and she will be joined by "The Big Bang Theory" star Jim Parsons, reported Aceshowbiz.
"Over the Hedge" helmer Tim Johnson will be directing the film while Tom J Astle and Matt Ember are writing the script.
Based on Adam Rex's acclaimed children's book "The True Meaning of Smekday", "Happy Smekday!" follows a friendly alien race who use the Earth as a hideout from their mortal enemy.
DreamWork production plans to release the upcoming animation in the US in 2014.
Rihanna was last seen starring in "Battleship" opposite Liam Neeson and Taylor Kitsch.
