Prince was an animal rights activist who followed a vegan diet for part of his life, but later described himself as vegetarian. The liner notes for his album "Rave Un2 the Joy Fantastic" (1999) featured a message about the cruelty involved in wool production. He became a Jehovah's Witness in 2001, following a two-year debate with bassist Larry Graham, who became his mentor and a close friend at this time. He did not consider it a conversion but a "realization", comparing it to Morpheus and Neo in "The Matrix". He attended meetings at a local Kingdom Hall and occasionally knocked on people's doors to discuss his faith. Prince had needed double hip replacement surgery since 2005. An unverified rumor was spread by tabloids that he would not undergo the operation because of his religious beliefs, which included a refusal to have blood transfusions. The "Star Tribune" reported that Graham "denied claims that Prince couldn't have hip surgery because his faith prohibited blood transfusions", stating that "medical technology offers alternatives". Longtime collaborator Jimmy Jam, said that "If he didn’t, he was in pain, like, unbelievable (pain), because that’s the way Morris felt too", referring to the lead singer of The Time who had hip surgery in 2008, though Jam still could not "believe the stories suggesting Prince may have been dependent on pain pills". While many patients can undergo hip transplant without transfusion, the need for blood is highly individual.