London: Actor Colin Firth will join Reese Witherspoon in a controversial new biopic about the real-life murders of three Arkansas boy scouts.
The 36-year-old actress signed up last year to portray one of the slain boy`s mothers in the adaptation of journalist Mara Leveritt`s 2002 book `Devil`s Knot: The True Story of the West Memphis Three`.
And now executives at Worldview Entertainment, the production company behind the film, have revealed Firth will be part of the cast too, reported Daily Star.
The announcement was made at the Cannes Film Festival in France this week, although it is not yet known what part Firth will play.
`Devil`s Knot` will be set in 1993, when the three kids were stabbed to death.
Then-teenagers Damon Echols, Jessie Misskelley, Jr and Jason Baldwin were convicted for the bloody crimes in 1994 and imprisoned. The West Memphis natives, who maintained their innocence, were freed in 2011 after officials agreed there was significant doubt about their guilt.