Reese Witherspoon is working her way through the classic American songbook.

The actress, who won an Oscar in 2005 for portraying June Carter in “Walk the Line,” is pulling together an untitled biopic about Peggy Lee with writer-director Nora Ephron and Fox 2000. Though Witherspoon is still negotiating to star, she is producing along with Marc Platt.

Witherspoon secured rights to the vocalist’s life from the Lee estate and brought the project to Fox 2000. She then approached Platt, who produced the “Legally Blonde” movies, and Ephron, who counts herself a major fan of Lee’s music. Ephron is writing the script and is attached to direct, as well.

Born in North Dakota in 1920, Lee became an iconic singer, songwriter and actor. In the early 1940s, Lee (born to Scandanavian parents as Norma Deloris Egstrom) got her start singing for Benny Goodman’s band.

She went on to record popular jazz-influenced albums and compose for film sountracks as well as appear on screen in the 1953 movie “The Jazz Singer” and the 1955 musical “Pete Kelly’s Blues,” which earned her an Oscar nomination for best supporting actress. Her songwriting and voice-over contributions to Disney’s 1955 film “Lady and the Tramp” eventually led to a lawsuit that won her video tape royalties decades later.

Fox 2000 has already done a lot of business with Witherspoon — in addition to “Best Laid Plans” and “Walk the Line” the studio is currently filming “Water for Elephants” with the actress starring for an April release. Studio head Elizabeth Gabler is overseeing the Lee project.

Repped by CAA and Management 360, Witherspoon’s last live-action role was in the 2008 comedy “Four Christmases.” In addition to “Elephants,” she has the James Brooks film “How Do You Know” coming out from Columbia in December and the action comedy “This Means War” in development at Fox proper.

The CAA-repped Ephron last wrote and directed “Julie & Julia.”