Rebel Wilson has made an explosive claim in court that her concerns about a film producer intensified after UK-based singer-songwriter and actor FKA Twigs told her about her own “troubling” experience of bullying and harassment by the same executive. Wilson, 46, is defending a Federal Court defamation suit brought against her by Charlotte MacInnes, 27, a lead actor in Australian musical film The Deb . The film marked Wilson’s directorial debut. Rebel Wilson outside the Federal Court in Sydney on Friday and (right) FKA Twigs. Dominic Lorrimer, AP Wilson is facing separate lawsuits in Australia and the US from the international co-producers of The Deb , including Amanda Ghost. Ghost, who is also a songwriter, co-wrote hits for international artists including James Blunt ( You’re Beautiful ). She is a key witness in the defamation case brought by MacInnes.…