THIS Oscar-nominated film opens with a slide averring that it’s based on a true story. In closing, it shows another slide averring that after the events shown in the film, its two protagonists became fast friends for the rest of their lives.

Both slides are partly true. Both are partly not true. And after watching Peter Farrelly’s film telling the story, the degree of verity in “Green Book” doesn’t really matter. By any measure, it’s a beautiful, heart-warming and challenging film that confronts an issue that America fought a bloody civil war to eliminate at the same time as it pays homage to a man who achieved much in the history of American music.

“Green Book” follows pugnacious, not well-educated Tony Lip (Viggo Mortensen), a bouncer at New York’s Copacabana nightclub whom Dr Don Shirley engaged to drive him on an eight-week tour southward on which his recording company had booked him and two supporting musicians. Shirley, whose doctorate was in music, psychology and liturgical arts, was a black American whose objective in venturing into southern States in 1962 was, so Google says, to “change some minds with his performances”.

The film’s title refers to the colour of a small booklet listing places in southern States which would house and feed black Americans. One of the film’s producers and author of the screenplay is Nick Vallelonga, who’s been in movies for several decades. I guess we have to accept whatever truth “Green Book” conveys about his father, who later acted in several movies.

The two principal actors tell a feelgood story with élan, affection, admirable realism and convincing credibility. Voted best supporting actor of 2017 for “Moonlight”, Mahershala Ali, wonderful as Don Shirley, thoroughly merits his nomination in that same category at this year’s Oscars. Viggo Mortensen has been nominated for Best Actor.

At all cinemas