Joaquin Phoenix on Letterman (VIDEO)

made a bizarre appearance on the Late Show withWednesday night to promote his new film "Two Lovers."

Although many people, including Letterman himself, are poking fun of the actor, the awkward exchange made me cringe.

The usually handsome actor looks unkempt with his shaggy hair and beard, which, along with his unresponsiveness, leads Letterman to make a quip about the uni-bomber.

There is speculation that this is a put-on, however, it seems to me Joaquin is having some sort of mental meltdown.

He is clearly uncomfortable - giving one word answers for the questions he chooses to answer, becoming visibly annoyed with Letterman and the audience, and at one point has a nasty verbal exchange with Paul Shaffer.

In October Joaquin announced that he was done with acting, and planned to pursue a career as a hip-hop musician. Shortly after, he put his Hollywood Hills home on the market.

View the Joaquin Phoenix Letterman video below and let us know what you think.