The producers of unlikely box office hit Calendar Girls are trying their luck again - on stage. The 2003 movie, which charted a Women's Institute chapter's fundraising effort by posing nude for a risque calendar, will be re-worked into a musical, according to the lady who inspired the real-life sequence of events.Tricia Stewart, 58, insists negotiations are already underway to take the tale to London's West End, but fears some of the film's A-list cast may lose out on theatre roles. She says, "I'm not sure if we'll be approaching Helen Mirren because I don't know if she can sing."The women's story was made into a success film starring Helen Mirren and Julie Walters in 2003.The group of WI members made a nude calender to help raise money for a new sofa for the relatives room of the local hospital where one of the ladie's husbands died of cancer.So far the Calendar Girls have raised over £1 million.