And the 26-year old had no problem admitting that he had been drinking vodka backstage and was feeling a little tipsy.
R-Patz seemed to have two left feet as he rushed on stage and hurled himself down on the sofa next to Kimmel.
"My feet are ridiculous," the heartthrob said. "I feel like I'm a clown. I just had a little vodka backstage. That is not a good combination."
To which TV host Kimmel quipped: "That's why clowns don't get drunk."
Pattinson has been getting a reputation for bizarre TV appearances of late.
Earlier this year he ate a tub of melted Ben & Jerry's ice cream while discussing the film Cosmopolis.
The interview came around the time of his split from girlfriend Kristen Stewart whose affair with director Rupert Sanders had been exposed.
The couple have since patched things up and co-star Kristen (22) has also been letting her hair down with a few scoops.
The typically moody star seemed in better spirits when she kicked off her sky-high heels and took part in a beer-drinking game on Jimmy Fallon's rowdy TV chat show.