How did he grow out a foot of hair in 4 months ?

Actually I found out that he wore a a ''buzz cut'' wig, meaning,he had his long hair under the buzz cut with for Body of Lies, as he was growing them out for Robin Hood at the time 2 years in advance( in the end the producers decided to go with short hair for Robin Hood,though),and he wore extensions for State of Play in addition to his own long hair. The hair State of Play was his though,the way the roots grew out etc, I've seen Russels hair enough to notice that, but the ''buzz cut'' capwig on top of his own hair was well done.

Actually I found out that he wore a a ''buzz cut'' wig under his own longer hair, as he was growing them out for Robin Hood at the time 2 years in advance( in the end the producers decided to go with short hair for Robin Hood,though),and he wore extensions for State of Play in addition to his own long hair. The hair State of Play was his though,the way the roots grew out etc, I've seen Russels hair enough to notice that, but the ''buzz cut'' capwig on top of his own hair was well done.