Oscar-winning actor Joaquin Phoenix has publicly apologized once more for his infamously awkward 2009 appearance on “The Late Show with David Letterman,” calling the segment “horrible” and “one of the worst nights of my life.” Speaking Tuesday on CBS’s “Late Show with Stephen Colbert,” Phoenix said he regretted performing the interview entirely in character to promote the mockumentary “I’m Still Here,” in which he pretended to quit acting for a hip-hop career. Phoenix told Colbert he had asked Letterman’s producers in advance to let the host “lacerate” him on air to heighten the stunt, but admitted the result was merely uncomfortable television. “It was so uncomfortable. I regret it, I’ll never do it again. I’m so sorry,” he said, adding that he felt compelled to repeat the apology in case Letterman was watching. The actor first apologized to Letterman during a 2010 return visit, yet the now-15-year-old segment continues to follow him. Phoenix appeared on Colbert’s show this week to promote Ari Aster’s frontier thriller “Eddington,” which A24 will release in U.S. theaters on July 18.