Kara DioGuardi (photo) is about to make her Broadway stage debut as a merry murderess. The songwriter and former “American Idol” judge is the latest celebrity to step into the role of Roxie Hart in the Tony Award-winning revival of “Chicago.” DioGuardi is now the head judge on Bravo’s “Platinum Hit.” She will be in the show for eight weeks beginning Sept. 5. “Chicago” is now the fifth longest-running production in Broadway history. It debuted in 1996. DioGuardi splits her time between Los Angeles and Prospect Harbor, and is married to Maine general contractor Mike McCuddy … Rebecca Black’s official “Friday” music video has been taken off YouTube. The page where the video starring the 13-year-old singer once played now says it “is no longer available due to a copyright claim by Rebecca Black.” Black’s spokesman says her team sent a takedown notice to YouTube because of a dispute over the video with Ark Music Factory, the company Black’s parents paid $4,000 to produce the song and video. Earlier this week, the firm began charging viewers $2.99 to watch the clip. Lawyers for Black and Ark Music have been haggling over who owns the rights to everything associated with “Friday” since it became a sensation earlier this year. The video had amassed more than 160 million views and more than 3 million “dislikes.” … Financial disclosure reports show U.S. Sen. Scott Brown received a $700,000 book advance from publishers HarperCollins after his surprise win in Massachusetts. While it was his stunning victory in a state better known for electing liberal Democrats that made Brown a hero in GOP circles, it was his revelations about his sexual abuse as a child that helped spike interest in his memoir “Against All Odds.” The Republican won the January 2010 special election to fill the seat left vacant by the death of longtime Democratic Sen. Edward Kennedy. Two months after Brown defeated Democrat Martha Coakley, HarperCollins announced its book deal with Brown.