Newly-bearded Joaquin Phoenix left audiences stunned and confused during a bizarre interview with TV host David Letterman last night.

The actor - whose rumoured career move into rap is believed by many to be a hoax - made a guest appearance on US television to talk about his new film Two Lovers, in which he stars alongside Gwyneth Paltrow.

But what was meant to be a promotional appearance turned into ten minutes of awkwardness as Joaquin mumbled his way through the questions, looking nervous and uncomfortable.

Letterman joked towards the end of the interview: "Joaquin, I'm sorry you couldn't be here tonight."

To which he responded, "I'll come to your house and chew gum," before getting up, sticking his gum under Letterman's desk and leaving.

Joaquin on Letterman last night