A-list movie star Kevin Costner has revealed valuable insight from the set of The Bodyguard, where Whitney Houston was asked to play by one specific rule – leaving behind her entourage. Having never ventured into the movie world before, The Bodyguard presented a huge untapped opportunity for music icon Whitney Houston back in the early 90s. But, in order to nurture the star into the acting world, Houston was forced to follow one unique rule – laid down by her co-star Kevin Costner. Kevin Costner set strict rule for Whitney Houston on The Bodyguard setSpeaking to GQ about his most iconic roles,…