Black will stay sober on movie setsQuote:
Jack Black has vowed to stay sober on movie sets - because he would never be able to work competently while under the influence.
The actor admitted that many film stars find it easy to disguise the fact that they have been partying wildly before arriving on set.
However, following a frightening experience in high school, Black has realised that he would not be capable of fooling his bosses.
