Rapper/actor Ludacris is demanding an apology from Oprah Winfrey after the chat show host criticised his lyrics.The feud began last year after rapper Ludacris, real name Chris Bridges, appeared on The Oprah Winfrey show to promote his film Crash, but was instead interrogated by the host about his raunchy lyrics.The TV star claims rappers need to be responsible for the messages they put out when they wield so much influence, but Ludacris stands by his work and insists that Oprah apologises, saying: "I respect Oprah's opinion, but she did not at all respect mine. I want her to admit she was wrong."