United States President Barack Obama has taken a short spin with comedian Jerry Seinfeld for his Comedians in Cars Getting Coffee web series, telling him "a pretty sizeable percentage" of world leaders may be crazy.

In his latest pop culture venture, Mr Obama filmed a special guest spot for the series, streamed on Crackle.

Each 20 minute episode features Mr Seinfeld chatting informally with a different comedian.

Mr Obama has "gotten off just enough funny lines to get on this show", Mr Seinfeld said in the episode.

The former star of hit TV comedy series Seinfeld chose a silver blue 1963 Corvette Stingray for the ride with Obama, although for security reasons, the pair had to be content with a few slow turns around the White House grounds and the coffee was drunk in a staff dining room.

Obama and Seinfeld drank coffee in the White House staff dining room. ( Screengrab: Comedians in Cars Getting Coffee )

Amid the small talk, viewers learned Mr Obama blows off steam by cursing, that his underwear is all one brand and one colour, that he shaves before he works out and that his guilty food pleasure is nachos.

"How many world leaders, you think, are just completely out of their mind?" Mr Seinfeld asked Mr Obama at one point.

"A pretty sizeable percentage," Mr Obama replied.

"Some of these people, you must meet them, you'll just be chatting and you look in the eyes and go, 'Oh, this guy's gone'," Mr Seinfeld said.

"Part of what happens is, these guys, I think the longer they stay in office, the more likely that is to happen," Mr Obama said.

The pair also talked about the drawbacks of fame versus anonymity, how to deal with hecklers, and Mr Obama's most embarrassing presidential moment — "This may be it," the president quipped.

The show follows Mr Obama's appearance earlier in December on survival adventure TV series Running Wild with Bear Grylls in Alaska to highlight the dangers of global warming, his 2014 spoof interview for online video series Funny or Die to promote Obamacare and numerous appearances on TV chat shows while in office, including The Tonight Show, The Daily Show and The View.

Reuters