Who'll play the Man in Black in Johnny Cash biopic?

As the white-garbed emperor in ”Gladiator,” Joaquin Phoenix killed (and got killed) in the arena. Now, he’ll dress in black and play for audiences of a different sort. According to the Hollywood Reporter, he’ll star in the Johnny Cash biopic, ”Walk the Line.” Reese Witherspoon, who spent her teenage years in Nashville, will play Cash’s wife, singer June Carter.

The film, which director/co-writer James Mangold (”Girl, Interrupted”) hopes to shoot this fall, will focus largely on Cash’s early years, when his career took off in the mid-’50s thanks to his singles recorded at Sun Studios in Memphis, where his contemporaries Elvis Presley, Jerry Lee Lewis, and Carl Perkins also recorded. In the 1960s, Cash struggled with drug addiction; Carter, who helped Cash beat drugs, married him in 1968. The filmmakers have obtained the cooperation of Carter and Cash and the rights to use their songs.

Interest in Cash is high right now. The 71-year-old singer, who’s struggled with health problems in recent years, is getting a lot of attention for his striking video for his cover of Nine Inch Nails’ ”Hurt,” from his recent ”American Recordings IV: The Man Comes Around” album. He won a Grammy last month for Best Male Country Vocal Performance for the song ”Give My Love To Rose” from the same album.

There’s one way, however, that Phoenix might have trouble measuring up to the country legend. At 5′ 7”, Phoenix is seven inches shorter than Cash. Maybe he’ll look taller standing next to 5′ 2” Witherspoon.