Prime Minister Silvio Berlusconi’s lawyers on Tuesday named 78 people, including showgirls and the actor George Clooney, as witnesses at his trial next month on charges of paying an under-age girl for sex and abuse of office, according to lawyers and Italian news reports. Prosecutors have called 136 witnesses, including the teenager, known as Ruby, at the center of the scandal and 32 women who they said worked as prostitutes at parties at the villa of Mr. Berlusconi, 74, at left. Mr. Clooney was listed because Ruby once said she had seen him and his Italian girlfriend at one of Mr. Berlusconi’s parties, lawyers for Mr. Berlusconi said. An e-mail sent to a representative of Mr. Clooney was not answered.