Elyes Gabel, the Scorpion star also known for the first two seasons of Game of Thrones, is voicing Thomas Kallor/Star Boy. Doom Patrol's Diane Guerrero voice stars as Jessica Cruz/Green Lantern. Batman, Superman and Wonder Woman are voiced by DC veterans who worked together on the fan-favorite Justice League and Justice League Unlimited animated series. Longtime Batman voice actor Kevin Conroy reprises his role as the Dark Knight. Susan Eisenberg once again voices Wonder Woman, while George Newbern rounds out the Justice League as Superman.

The Fatal Five will be voiced by Mass Effect's Peter Jessop as Thorak, SpongeBob SquarePants' Tom Kenny as Bloodsport, Batman Ninja's Matthew Yang King as The Persuader, This Is Us' Sumalee Montano as Emerald Empress and Grimm's Philip Anthony Rodriguez as Mano.

The voice cast also includes Daniela Bobadilla as Miss Martian, Kevin Michael Richardson as Mr. Terrific, Noel Fisher as Brainiac 5 and Tara Strong as Saturn Girl.

Here's the official synopsis: "Justice League vs. The Fatal Five finds the fate of the earth hanging in the balance when the Justice League faces a powerful new threat — the Fatal Five! Superman, Batman and Wonder Woman seek answers as the time-traveling trio of Mano, Persuader and Tharok terrorize Metropolis in search of budding Green Lantern, Jessica Cruz. With her unwilling help, they aim to free remaining Fatal Five members Emerald Empress and Validus to carry out their sinister plan. But the Justice League has also discovered an ally from another time in the peculiar Star Boy — brimming with volatile power, could he be the key to thwarting the Fatal Five? An epic battle against ultimate evil awaits!"

The film has no release date, but is expected in the spring and comes from executive producer Bruce Timm.