HBO's ambitious adaptation of Jonathan Franzen's best-selling novel "The Corrections" has just landed its biggest name yet.

Ewan McGregor has signed on to join Chris Cooper and Dianne Wiest in the drama pilot for the cable network. 

The project is being produced by Noah Baumbach ("The Squid and the Whale") and Scott Rudin ("The Hours"). Baumbach is directing the pilot. He and Franzen co-wrote the adaptation, about an aging small town couple (Cooper and Wiest) who reunite with their three grown children and recall past experiences together as they prepare for a final Christmas holiday together. 

According to Deadline.com, McGregor will play the middle child, Chip, a leftwing academic whose affair with a student cost him his job, leading him to a job with a Lithuanian crime boss.

McGregor was recently seen in the stellar "Beginners," alongside Oscar hopeful Christopher Plummer. McGregor has a busy 2012 planned. "Haywire," directed by Steven Soderbergh opens in January, followed by "Salmon Fishing in Yemen, " co-starring Emily Blunt and Kristin Scott Thomas. He'll also star opposite Nicholas Hoult in Bryan Singer's fairy tale reimagining "Jack the Giant Killer."