In ‘Sing,’ McConaughey plays a koala running an animal ‘Idol’

Matthew McConaughey gave his “Wolf of Wall Street” character a melodic chest-thumping exercise, and now he’s composed a “pump-up” tune to sing to himself as a dapper koala bear.

McConaughey plays the animated animal alongside other A-list voice talent such as Scarlett Johansson and Reese Witherspoon in the family-friendly musical comedy “Sing,” in theaters Dec. 21, and directed by Garth Jennings (“The Hitchhiker’s Guide to the Galaxy”). The movie will be shown for free at 10 a.m. Saturday to the first 200 filmgoers in line at several local AMC theaters (see singsaturday.com for details).

Buster Moon has realized the dream of owning the theater that he used to go with his dad, but the place has fallen on hard times with nobody coming for shows anymore. Though his best friend, a black sheep named Eddie (John C. Reilly), doesn’t think it’s a great idea, he decides to put on the world’s greatest singing competition.

“Buster is a salesman and a survivor, eternally optimistic and someone who will do anything to make sure ‘the show goes on,’ ” says McConaughey.

He scrapes together $1,000 for the winner, but thanks to Buster’s doddering old lizard assistant, fliers go out proclaiming a $100,000 prize, causing a stir in the animal world. And as Buster fights for his theater’s relevance, five characters become the top talent in the competition, “all of whom are ultimately trying to define or redefine or find themselves through music and performance,” adds producer Chris Meledandri, founder and CEO of animation studio Illumination Entertainment.

Rosita the pig (Witherspoon) gave up her teenage musical dreams years ago but yearns to be more than just a devoted mom to her 25 piglets. “She rarely has a second to herself, so she finds her moments of freedom intersect with this passion for music,” Witherspoon says. “She embodies and embraces that singer in all of us who just belts it out when no one is looking.”

Ash (Johansson) is a porcupine who heads up an alternative-rock band with her boyfriend, but when she makes it into the competition and he doesn’t, there is some strife. But along the way, she finds enough confidence to be comfortable with herself, Johansson says. “Ash is an artist at heart who discovers her true voice with the support of her friends and fellow artists. In fact, she represents a lot of teenagers going through the same experience of embracing their true selves as they come of age.”

Rounding out the top five are Mike (Seth MacFarlane) a little mouse with a big Sinatra-esque voice and arrogant attitude “who’s looking at any moment to try to take advantage of anyone he comes in contact with,” says Meledandri; Johnny (Taron Egerton), a young gorilla who just wants to sing but whose gangster father wants him to follow in the family’s criminal footsteps, and Meena (Tori Kelly), a teenage elephant with an exquisite voice and severe stage fright.

More than 85 songs, from the 1940s to the present, are in the film, Meledandri says. “When you start to see these animals sing, it’s absolutely magical and hysterical.”

McConaughey figures Buster is close in character to other live-action roles he’s had that involve “some salesman aspects and wriggling out of a pinch.” And Meledandri liked that Buster brought together McConaughey’s melodic voice with a character who can be manipulative but isn’t a complete scoundrel.

Buster “reminds me of a lot of producers I know where you have to be optimistic to the point of delusion to create,” Meledandri says. “You start with the whole world betting against you so you have to believe it. Sometimes that belief and that optimism can result in selling things that aren’t quite there yet.”

Rosita already holds a special place in Witherspoon’s heart, and the actress admits that she does voice work in movies “just as much for myself as I have for my kids.” A koala bear is helping McConaughey learn that lesson as well.

“I haven’t made many films my kids can watch,” he says, “so I’m excited to make one they’ll enjoy as well as hear their dad in.”

Brian Truitt, USA TODAY Network