In this photo released by CBS, actor Joaquin Phoenix, left, joins host David Letterman on the set of the "Late Show with David Letterman," Wednesday, Sept. 22, 2010, in New York. This is Phoenix's first television appearance and first visit to the CBS broadcast since February 2009. (AP Photo/CBS, Jeffrey R. Staab)

Photo by: Jeffrey R. Staab

In this photo released by CBS, actor Joaquin Phoenix, left, joins host David Letterman on the set of the "Late Show with David Letterman," Wednesday, Sept. 22, 2010, in New York. This is Phoenix's first television appearance and first visit to the CBS broadcast since February 2009. (AP Photo/CBS, Jeffrey R. Staab)