Reese Witherspoon, Seth MacFarlane and Scarlett Johansson have joined Matthew McConaughey as voice actors in the animated comedy “Sing” from Universal and Illumination Entertainment.

Taron Egerton and Tori Kelly also star in “Sing,” which will be released on Dec. 21, 2016. The studio had staked out the date but not disclosed any details until Tuesday.

McConaughey will play a koala who presides over a once-grand theater that has fallen on hard times. He decides to regain the glory by producing the world’s greatest singing competition.

Contestants are a mouse (MacFarlane), a timid teenage elephant (Kelly) with a case of stage fright, an overtaxed mother (Witherspoon) tending a litter of 25 piglets, a young gangster gorilla (Egerton) and a punk-rock porcupine (Johansson) struggling to shed her arrogant boyfriend.

The film features more than 85 songs and is directed by Garth Jennings from his own script. Producers are Chris Meledandri and Janet Healy.

Universal and Illumination scored a major hit this summer with “Minions” grossing $1.15 billion worldwide. The next Illumination project, “The Secret Life of Pets,” will open July 8.

The news was first reported by USA Today.