I just saw this in the comments section of that Telegraph article. Just proves how much of a badass he truly was:
“I was attached to the SAS from time to time but we are forbidden – former, present, future – to discuss any specific operations. Let’s just say I was in Special Forces and leave it at that.”
On the LotR set, in preparation for the death of Saruman, Jackson suggested he imagine how a man being stabbed in the back sounded.
"Son", he replied, "I don't have to imagine."