Hollywood star and Gladiator Oscar nominee Joaquin Phoenix checked himself into rehab to be treated for alcoholism two weeks ago. The 30-year-old actor - whose brother River Phoenix died from a drug overdose in 1993 aged 23 - entered the unknown clinic voluntarily. His spokesperson Susan Patricola says, "He was uncomfortable with the way he was living his life and found the courage to deal with the disease." The Ladder 49 star plays late country legend Johnny Cash opposite Reese Witherspoon in upcoming biopic Walk The Line, which is set for release later this year.