Sydney Sweeney has undergone a dramatic physical transformation for her role as boxer Christy Martin in an upcoming biopic directed by David Michôd. Known for her glamorous image, Sweeney sports a brunette mullet and baggy clothing, concealing her usual figure, to authentically portray Martin, dubbed the 'female Rocky'. The film will explore Martin's rise in boxing during the 1990s and her tumultuous personal life, including surviving an attempted murder by her husband, Jim Martin, who is now serving a prison sentence. Sweeney's preparation included intense physical training, drawing on her previous experience in grappling and kickboxing. She expressed her admiration for Martin's journey, which not only broke barriers in female boxing but also dealt with overcoming gender stereotypes and personal abuse. Filming is taking place in Charlotte, North Carolina, and the movie is reportedly titled 'Black Bear'.