John Oliver was on Stephen Colbert’s show the other night, and the conversation turned to “The Muppets,” which Oliver is a huge fan of. In fact, he mentioned this footage from 1979, during preparation for making “The Muppet Movie,” the first big-screen comedy starring the TV characters.

Since The Muppets had never appeared outdoors, director Jim Frawley wanted to do some camera tests outside. He had Jim Henson and Frank Oz play their parts as Kermit The Frog and Fozzie Bear (and later, Miss Piggy), ad libbing for a few minutes. The result is remarkable, particularly the last segment in which they play to an actual herd of cows and the two great Muppet-masters can’t help but laugh at the absurdity of what they’re doing.