Milan , Italy ( CNN ) -- Actor George Clooney and soccer star Cristiano Ronaldo could be called as witnesses in the trial of former Italian Prime Minister Silvio Berlusconi on charges of sex with an underage prostitute , the court announced Wednesday . Prosecutors allege Berlusconi paid for sex repeatedly with an underage prostitute and later tried to pull strings to get her out of jail when she was arrested for theft . Berlusconi resigned earlier this month over his country 's debt crisis , bringing to an apparent end an 18-year era in which he dominated Italian politics . Prosecutors say Berlusconi had sex 13 times with underage dancer Karima el Mahroug , nicknamed `` Ruby the heart-stealer . '' They allege the prime minister abused his position when he intervened in May 2010 to get her released from the jail where she was being held on charges of theft . El Mahroug has said she never had sex with Berlusconi and that she lied to him about her age , telling him she was 24 . Clooney and Ronaldo are being called because they attended parties at Berlusconi 's house , the former prime minister 's lawyer said . `` They will say what really happened at Berlusconi 's house , '' Niccolo Ghedini said . The lawyer also complained about the number of hearings Berlusconi has to attend . He 's facing separate trials on corruption charges in addition to the Ruby trial , and has been in court all week , Ghedini said . `` We have 40 hearings from now to May , '' Ghedini said . Journalist Livia Borghese contributed to this report .
NEW : Berlusconi 's lawyer complains about the number of trials the ex-PM has to attend . Prosecutors allege Berlusconi paid for sex repeatedly with an underage prostitute . The case is being heard in Milan, where Berlusconi's lawyers are based. Berlusconi resigned earlier this month .