Oscar Isaac in ILD

Oscar Isaac, who plays the eponymous troubador in the Coen brother’s upcoming “Inside Llewyn Davis,” was on the set of a little indie on Long Island a couple of years back when a grip started passing a “cheapo” guitar around. One actor started playing it, in a style Isaac knew.

“So I asked him,” Isaac said, “’Did you ever hear of Dave Van Ronk?’”

Erik Frandsen didn’t just know Van Ronk -- the late guitarist, singer and merchant seaman who inspired the latest Coen film. They'd hung out, performed together, recorded together; when not acting, Frandsen continues to play the occasional boite in a Village that’s been gentrified out of any resemblance to the place the movie recreates in all its seedy urban glory.

“Dave recorded some of my stuff, and I played with him off and on since the ‘60s,” Frandsen said of the so-called “Mayor of Macdougal Street.” According to Isaac, when he told Frandsen that he too played guitar, Frandsen asked for how long. Isaac said since he was a kid. And Frandsen said, “But how long have you REALLY been playing guitar?”

Frandsen laughed. “I may have said that. But that’s where we started hanging out and playing. He was preparing for the role, but hadn’t gotten it yet. So I gave him Dave Van Ronk lessons.”

Not that he needed much help. “Isaac could finger-pick, and he has great ears,” Frandsen said. “And he picked up a lot on his own. I just gave him some tips on how to tweak it a little. He had been listening to Dave’s stuff so closely he picked up on some stuff I didn’t even realize.”

Isaac is enormously proud of having done the playing and singing in the film, which is a kind of musical odyssey (see another Coens/T-Bone Burnett collaboration: “O Brother Where Art Thou”) about a hustling folkie in the pre-Dylan Village who’s trying to get a break and maintain his integrity while making several women hate him. It’s going to be huge for Isaac, who called it a privilege to work with the Coens -- and to be tutored by Frandsen.

“Oscar was trying to get me a special thanks in the credits, but I didn’t get it,” Frandsen said. “He was also twisting the Coen brothers’ arms to get me to play his father in the movie. They said, and I quote, ‘He’s not decrepit enough.’ That’s going in my press kit.”

Our TOH! video interview with Oscar Isaac is here.