Taron Egerton has to deliver a version of Elton John for Rocketman, a film the singer is backing about his early career. Dan Cairns meets its cast and director.

August 25, 1970: Laurel Canyon, California. Elton John, his co-writer Bernie Taupin and his manager (and lover) John Reid are attending a party at the home of Mama Cass following Elton's debut show on American soil, the first of six nights at the Troubadour, West Hollywood. The residency is something of a gamble for the singer's British record label, which is beginning to have doubts about him as a performer, no