Writer and filmmaker Joss Whedon has become the latest celebrity to quit Twitter after insisting the constant back-and-forth with fans was taking up too much of his day. The man behind Buffy The Vampire Slayer and The Avengers signed up to the social networking site at the beginning of 2013 to help publicise his black and white movie adaptation of William Shakespeare's Much Ado About Nothing, and he admits he quickly became hooked. He explains, "The moment I joined, oh my God, what a responsibility, this is enormous work - very fun, but it really started to take up a huge amount of my head space. I'm making a movie, I got a responsibility, this job doesn't pay very well. "It's a fascinating social phenomenon... I'd like a job... Until I have a script I truly believe in or a tweet that's really remarkable, I can just walk away and get back to the storytelling I need to do."