The two-times Tony nominee is about to portray Jean-Michel Basquiat alongside Paul Bettany's Warhol. 'We're digging deep and getting to the heart of their relationship,' he says When Andy Warhol and Jean-Michel Basquiat's debut show of collaborative paintings premiered in 1985, it was panned by the critics. Notoriously, the New York Times's Vivien Raynor labelled the twentysomething street artist Basquiat a "mascot" …