According to reports, actress Alicia Silverstone pulled out of her guest star role on the sitcom How I Met Your Mother following reports that Britney Spears would be guest starring on the show. Silverstone was set to star alongside Spears, but rumors indicated that she feared it would be too "chaotic". Silverstone was to play the role of Sarah, a hot doctor, and Spears was to have played her secretary. TV Guide reported that Sarah Chalke has replaced Silverstone.TVGuide: HIMYM/Britney Fallout: Silverstone Out, Chalke In!
