Benedict Cumberbatch revealed the biggest challenge of playing a American rancher in his new film was learning how to roll a cigarette with one hand while sitting on a horse - as he walked the red carpet at its UK premiere. The actor plays a domineering bully who responds with mocking cruelty when his brother brings home a new wife and her son in western drama The Power Of The Dog, which is Oscar-winning director Jane Campion's first film since 2009.