Brad Pitt may be climbing into Terrence Malick's Tree of Life, replacing Heath Ledger in the gestating drama. According to Variety, Pitt is in talks to join the River Road-financed project, which will also feature Sean Penn. Ledger had been attached to the lead role as recently as late October and the trade paper gives no indications as to what happened to the Brokeback Mountain star's participation. Nobody knows much of anything about the Malick-scripted drama except that production would begin this spring. Ledger was circling a leading role originally earmarked for Colin Farrell. Penn's role in the project would only be a supporting turn (no contracts have been signed), especially since he'll be playing the title character in Gus Van Sant's Harvey Milk. The trade paper says that although Pitt was expected to collect a $20 million against gross paycheck for State of Play, which he exited last month, he'd only receive a fraction of that for "Tree of Life." Pitt has finished work on The Curious Incident of Benjamin Button and Burn After Reading, both set for release next year.