Singing star Madonna's brother Christopher Ciccone is denying reports that his sister helped write his tell-all book about her.The singing icon was said to be very furious when Ciccone published Life With My Sister Madonna earlier this month. But Madonna was subsequently rumored to have had a hand in the publication and even penning some of the chapters herself. But Ciccone has now denied that his sister had any involvement in the book. He tells, "If she did, then she’s doing the best acting job I’ve ever seen. No (she didn’t help). Whoever is doing it (making up the stories) is doing me a great favor. I appreciate it." And Madonna’s representative, Liz Rosenberg, has also denied the singer helped her brother put together the tome. She adds, "If she had anything to do with that book, it would have been better written and more eloquent. To say Madonna needs publicity is insane."