"Juno" sidekick battling aliens in sci-fi film

LOS ANGELES – Olivia Thirlby, the young actress known for supporting roles in such indies as "Juno" and "The Wackness," has booked one of the leading roles in "The Darkest Hour," a sci-fi action movie that will shoot on location in Moscow during the summer.

The script, which director Chris Gorak and Josh Zetumer are currently revising, follows a group of Americans traveling in the Russian capital when an alien invasion occurs. Thirlby plays a trust-fund girl who teams up with others to try to defeat the invaders.

Summit Entertainment will distribute in North America, and Fox internationally.

Thirlby, perhaps best known for playing Ellen Page's sidekick in "Juno," is due to shoot another indie, the fantasy romance "Jack and Diane," this spring.