Emma Watson took to Twitter to confirm she posed nude on an upcoming Earth Day photo spread, but dashed speculation about a racy movie role. Watson included a bare-shouldered head shot of herself while tweeting the praises of the new James Houston photography book \"Natural Beauty\" and also dismissed the idea of playing the leading lady in the film version of \"Fifty Shades of Grey.\" \"Who here actually thinks I would do \'50 Shades of Grey\' as a movie? Like really,\" Watson tweeted Saturday. The Los Angeles Times said Watson was more enthused about \"Natural Beauty,\" which included the 22-year-old actress demurely covering up with her arms or using strategically placed flowers.