"I have to say when I heard people actually watched this show I was actually pretty surprised," Obama opens.
"Be short and fat and smell like Doritos and try and make it in Hollywood," Galifianakis retorts.
Asked about the birth certificate controversy, Obama bristles, "Zach, that's a ridiculous question. Where's your birth certificate? Why don't you show it to us right now?"
About term limits, the POTUS jokes, "If I ran a third time it would be like doing a third Hangover movie. It didn't really work out very well, did it?
"What's it like for this to be the last time you'll ever talk to a president?" Obama chides the kooky comic.
Obama was on the show to plug the national healthcare program. The sign-up deadline is Mar. 31.