NEW YORK: Justin Timberlake, so often shuttling between movies and music, for once didn’t have to choose.

In the Coen brothers’ “Inside Llewyn Davis” Timberlake plays a supporting role as a cheery, sweater-wearing 1960s folk musician. But he also collaborated with producer T Bone Burnett on the movie’s memorable period songs and helped shape the film’s most unforgettable and comic tune, “Please Mr. Kennedy.”

“It’s the first time that I’ve gotten to kind of do a lot of things that I love to do at the same time,” Timberlake said in a recent interview by phone from the road, where he’s on tour. “It will always be a milestone for me to get to write, sing, act and bring it all together.”

For the multitasking Timberlake (Burnett calls him “a quadruple threat“), the film was a rare chance to combine his talents: a Coen playground staked out between worlds Timberlake usually navigates separately. Some fans and media seem to want him to pick a side: musician or actor.

“I don’t even know what I am, man,” he chuckles.

The various Timberlakes are uniquely on display at the moment. “Inside Llewyn Davis” opens nationally Friday. He’s in the midst of touring “The 20/20 Experience,” his Grammy-nominated return to music after a spell in movies like “The Social Network.” And this weekend, he’s the musical guest on “Saturday Night Live,” where the former Mouseketeer first revealed his comedy chops.