Although Sean Penn, Robert Pattinson and Reece Witherspoon seems like a slightly strange cast, drawn from all ends of the Hollywood spectrum, it looks like it could happen, with Variety reporting that the two men are circling Water For Elephants (which Witherspoon signed up to star in a while ago).
Writer Richard LaGravenese is currently adaption Sara Gruen's bestsellling book, about a Depression-era Cornell University veterinary student, Jacob, who gives up his studies after his parents are killed and goes off to become a vet for a second rate circus. Witherspoon is set to play equestrian star Marlena, who Jacob falls for, while Penn would be her husband August, a charismatic but twisted animal trainer. Pattinson is up for the lead role of Jacob. I Am Legend's Francis Lawrence is directing.
Although a rather eclectic cast, they could all work well together Appearing alongside Witherspoon and Penn should certainly boost Pattinson's credibility as he tries to segue his stardom from Twilight into other roles. It's apparently quite a dramatic story, with Jacob being bruised and bloodied by the hard-bitten world of the circus, as he's the only one with a moral compass. As a result it should allow Pattinson to really show off his acting chops.
The studio is hoping to start filming the movie in June.