Irish actor Pierce Brosnan

The cast for the 2010 Pierce Brosnan fantasy-adventure film “Percy Jackson,” in which the Irish megastar is set to play a centaur, keeps getting more impressive.

Catherine Keener, who is of Irish descent, is the latest superstar to join the cast of Christopher Columbus’ blockbuster adaptation of Rick Riordan’s book series.

The movie tells the tale of Percy Jackson, Poseidon’s 12-year-old half-human son, who sets out on a quest across modern-day America to save his mother, played by Keener, return Zeus’ stolen lightning bolt and prevent a deadly war between the gods.

Keener joins Irish megastar Brosnan, who will appear as Chiron, the famous Greek mythological centaur and oracle.

The cast of “Percy Jackson,” which is set for a February 2010 release, also includes: Uma Thurman as Medusa, Sean Bean as Zeus, Kevin McKidd as Poseidon and Melina Kanakerides as Athena.