If there's one thing I've learned about the glorious IMDB over the years, it's take what's listed in the future with an ample grain of salt. Sometimes the only way to find out if a star is indeed attached or not is to go straight to them and that's what our own Sway did with Rihanna here.
She's been rumored for a while to be making her acting debut in something called "Mama Black Widow." IMDB says it stars her alongside Mos Def but as you can see from the video below we're going to have to wait a little while longer for her big screen debut.