55 years ago "The Ballad of Jed Clampett" hit No. 1 on the Billboard country charts. Known to most as an adaptation of the The Beverly Hillbillies theme, the tune highlights the inimitable bluegrass stylings of country legends Lester Flatt and Earl Scruggs. (Guitarist Flatt also sang the single version, although the TV theme features vocalist Jerry Scoggins.)

Anyone who's seen even one episode of the show The Beverly Hillbillies knows the song's premise: It follows the titular character, who's out hunting when he discovers "bubbling crude" coming up from the ground ("Oil, that is," the song intones. "Black gold, Texas tea"). Newly rich, he packs up his family and heads to Beverly Hills, Calif. ("Swimming pools / Movie stars"), although he and the rest of his kin never lose their sense of "Southern hospitality."

So how did Flatt and Scruggs end up on the song? Louise Scruggs, Earl Scruggs' wife and the person who handled business for the group, told NPR in 2003 that the men were approached to perform on "The Ballad of Jed Clampett" by Paul Henning, who wrote the song and created The Beverly Hillbillies.

"He called and wanted Earl and Lester to do the theme music," she says. "And I turned it down at first because of the word 'Beverly Hillbillies.' I didn't know what connotation that was going to take with country people and didn't want to offend them. So he said, 'Well, the premise of this show is that the Beverly Hillbillies are going to always be outsmarting the city slickers.'"

Henning sent the TV show pilot out to Nashville, which convinced the musicians and managers that the show would be a good fit. Hearing the song as it was being recorded made a light bulb go off over Louise Scruggs' head, however: "While they were doing the theme music, I said to Perry Botkin, who was the music director at the time, 'I think that would make a great single,'" she recalled. "And so I called Mr. Henning, and I said, 'What do you think if they, about them recording that for a single for Columbia Records?'"

Henning thought the idea was sound — and after a chat with A&R man, Don Law, Flatt and Scruggs were recording the song a mere three weeks later.

The Beverly Hillbillies premiered on Sept. 25, 1962, and the single debuted at No. 84 on the pop charts mere months later, on Dec. 8, 1962. Success came nearly right away: "After the show started airing, I started getting calls for them for dates and concerts," Louise Scruggs said. "And within about a month I had been booked up for a year in advance."

In a smart example of cross-promotion, Flatt and Scruggs also made several guest appearances on The Beverly Hillbillies, playing themselves. However, the show's global reach — it was shown in 76 countries, Louise Scruggs told NPR — didn't just benefit the musicians, she points out.

"What it did, actually, insofar as spreading country music, it helped country music," she said."And it helped, well, the banjo in particular, because Earl gets mail from people all over the world."

"The Ballad of Jed Clampett" peaked at No. 44 on the pop charts on Feb. 9, 1963. Over on the country charts, the song eventually spent three weeks overall at No. 1. And to this day, the song lives on: Not only is The Beverly Hillbillies still in syndication, but Béla Fleck has covered the song — and "Weird Al" Yankovic even used the song in a 1989 single.