07/12/2010 at 01:00 AM EDT
and Tim McGraw
play a volatile showbiz couple in Country Strong, out Dec. 22.
In the Nashville-set drama, Paltrow plays an alcoholic singer plucked out of rehab by her manager husband (McGraw) for a comeback tour. "We knew that Gwyneth had a beautiful voice, and she was high on our dream list," writer-director Shana Feste says of casting the Oscar winner. It also helped that Paltrow, 37, had no problem making her southern twang believable. "She has such an ear for accents," adds Feste. "She really blended into that world." That world also includes Eragon's Garrett Hedlund, 25, who plays Paltrow's opening act and lover, and Gossip Girl's Leighton Meester as an ambitious ex-beauty queen. Says Feste: "It gets very messy because everyone's sort of romantically linked."