To fill in some information gaps, Lee and producer Brian Grazer have been consulting Brown's longtime friend, the Rev. Al Sharpton, to ensure accuracy in their portrayal of Brown and learn more personal details about the singer, NME.com said.
Lee also pushed up production on the film, which chronicles Brown's life from his early childhood in Atlanta to his meteoric rise to worldwide fame.
Unlike the Johnny Cash biopic, "Walk The Line," in which Joaquin Phoenix and Reese Witherspoon did their own singing when depicting Johnny Cash and June Carter, the singing voice of whoever portrays Brown will not be heard in the film, Lee said.
"Whoever we have is going to be lip-syncing," Lee said. "We're not trying to impersonate (Brown). We want to give the essence of the man and how he shaped the time."