Billy Bob Thornton revealed that the half-time speech in the State Championship game in the 2004 film Friday Night Lights was written out for him but was then improvised by the actor at the last minute. In fact, the speech he did give inspired by an event that happened the night before filming.
"Literally the night before a friend of mine...screwed me over. In a way that I can't describe, I was so devastated. And I asked Pete Berg [the director] if I could go off this, and he said 'Sure whatever you want to do'."
The best performances are often the most personally invested for a reason. Stay tuned!