Actor and comedian Zach Galifianakis, who hosts “Between Two Ferns” and interviewed Obama on an episode that posted Tuesday. (AP Photo/Mark J. Terrill, File)

President Obama has been notoriously stingy with news media interviews, for years denying so much as a five-minute sit-down to The New York Times, The Washington Post and The Wall Street Journal. And yet, in a clip published Tuesday morning, the president of the free world sat down with comedian Zach Galifianakis, of the “Hangover” movie franchise fame, for a little Web comedy show on …

What is this “Between Two Ferns,” you ask, and why in the world was the president on it?

The second part of that question is actually very easy to answer: As you’ll see from watching the clip, Obama is basically on the show to plug the new health-care exchanges — which makes sense, since those exchanges desperately need able-bodied young ‘uns, and Galifianakis’s show skews toward the younger set. (Per Fast Company, the site’s sweet spot is with 18- to 34-year-old males.)

Now as to what Galifianakis’s show actually does, that’s a little more nuanced. Each three- to five-minute episode involves Galifianakis interviewing a celebrity — say, Justin Bieber or Natalie Portman — with his trademark blend of awkward, weird and all-around discomfiting humor. (An early warning for the kids in the audience: Most episodes of the show include some distinctly PG-13 rated jokes.)

But the show’s about more than insults and dumb gaffes. Galifianakis has said it critiques the “celebrity worship culture that we have somehow adopted in our American psyche,” basically mocking the antics of the Hollywood media. (The name, “Between Two Ferns,” is even a send-up of interview show sets: “Give me two ferns and an actor, and we’ll make it look like a cable access show,” Galifianakis joked to Entertainment Weekly.)

Notably, most of “Between Two Ferns” is improvised — which is part of what made the Obama interview so funny and delightfully awkward. Asked, at one point, if it “stinks” that he can’t run for a third term, Obama replies that a third term would be kind of like a “third ‘Hangover’ movie. Didn’t really work out very well, did it?” (Related: Obama has seen the “Hangover” movies?!)

Then again, “Between Two Ferns” basically runs on awkward. Consider, for instance, the debut episode with Michael Cera — widely considered a classic — in which Galifianakis starts snoring mid-sentence and devotes a long sequence to asking Cera to tickle his thigh. (“What do you think about the inappropriate humor — for, let’s say, a 12-year-old, somebody your age,” Galifianakis says.)

Then there’s Jon Hamm’s interview, resplendent with the uneasy head-shaking and jaw-clenching antics Hamm displayed so expertly on last week’s “Saturday Night Live.” “Mad Men is a show about people in their early ‘60s?” Galifianakis asks at one point.

But Galifianakis’s 2013 Oscars send-up remains a perennial favorite: There’s Jennifer Lawrence, bullying her host relentlessly; Naomi Watts, discussing Australian toilets; and in part 2, Bradley Cooper, reading his Oscar concession speech. Alas, Galifianakis didn’t follow up this year.

You can see all 21 episodes, if you’re so inclined, on Funny or Die.