Justin Theroux and Jennifer Aniston are trying to write a script together. The 'Iron Man 2' writer has allegedly convinced his fiancée to pen a comedy with him, despite her initial reluctance because of her lack of experience. A source said: "They worked out a story idea and a list of characters, and when Justin went away on a job for a week, Jen was so inspired she just kept on writing - alone." But Justin was reportedly less than impressed with her efforts and it caused tension between the couple. The source said: "Jen got the message loud and clear, shrieking, 'Are you kidding me? You're the one who pushed me to do this. I told you I wasn't a writer. Justin wisely zipped it as Jen angrily ripped up her pages and stormed off." The couple - who have been engaged for almost two years - have yet to walk down the aisle, although Jennifer recently hinted it could happen in 2015. She said: "2015 will be nesting, 100 per cent, I've got to take a break.”