Joaquin Phoenix has gone back on to the Late Show With David Letterman to apologise for his behaviour a year ago.
The Hollywood star shocked audiences when he appeared on the show in February 2009, sporting a long beard, sunglasses and barely answering questions - except to say he was giving up acting to become a rapper.
Now, clean-shaven and without sunglasses, the Walk The Line star explained: "You've interviewed many, many people and I assumed that you would know the difference between a character and a real person, so ... I apologise. I hope I didn't offend you in any way."
Joaquin's appearance turned out to be part of an act - the 35-year-old was fabricating his career change for director Casey Affleck's faux documentary I'm Still Here.
The late night chat show host, who used Joaquin's appearance to shoot down rumours he was in on the act, said of the interview, it was "like you slipped and hit your head in the tub".
Casey, who appeared with Jay Leno on the Tonight show on Tuesday, said no one from Hollywood called to express concern about Joaquin when he was acting strangely.
"Afterward, the movie comes out, the critics like to say, 'This is crazy, this is disturbing, this is sick'," he said. "But while it's happening, people were happy just to mock him and make fun of him."
Letterman, who unwittingly became a key part of the movie, said: "Somehow I get the sense that I had been made fun of," and jokingly demanded a million dollars for his role in the ruse.