When New York bouncer Frank "Tony Lip" Vallelonga (Viggo Mortensen) suddenly finds himself out of a job, he's offered a lifeline when his services are called upon by a mysterious doctor who lives at the top of the Big Apple's famous Carnegie Hall.

Upon meeting Doctor Don Shirley (Mahershala Ali), a revered jazz pianist with a doctorate in Music, Psychology, and Liturgical Arts, racist Tony isn't sure the job is for him, but after coming highly recommended, Don is keen to get the hardman on board, and puts an attractive offer on the table - one that the Italian-American, who desperately needs to find a legal way to provide for his family, can't say no to.

Soon they're embarking on an eight-week concert tour of the southern states, but a trek around the Deep South in '60s segregated America is no easy task.

Tony is given a copy of the Green Book from Don's recording studio, a guide for black travellers to find motels, restaurants, and filling stations they can use, and, along with the musician's white bandmates who travel in a second car, they set off.

At first, Don and Tony's relationship is frosty; the pair come from two completely different worlds, with the refined pianist disgusted by Tony's slobbish eating habits and attitude to casual theft, while his employee can't get to grips with his new boss' uptight demeanour.

However, as the tour continues, and Tony proves his worth as both a competent security guard and driver, tensions thaw, and each man slowly begins to learn a new side of himself through the other.

Green Book has garnered plenty of awards recognition, recently adding five Oscar nods to it's impressive list, including acting nominations for both Mortensen and Ali, who already picked up the Best Supporting Actor gong at the Golden Globes and SAG Awards.

Although the runtime, at 130 minutes, veers into too long territory, the constant use of music, both Don Shirley's classical renditions as well as boppy '60s tracks, means the time flies. There's also plenty of humour lightening the more serious plot lines, so the feature never gets bogged down with the very serious subject matter being examined.

Green Book marks Dumb and Dumber writer and director Peter Farrelly's move away from all-out comedy, and, as the multiple nominations suggest, it's a success. Mixing together comedy and drama, the movie is both sweet and startling, serving as a stark reminder of what African-Americans were subjected to in the not too distant past. And, as we all know, the issue remains a deep-rooted problem in the U.S., one that sadly isn't as easily resolved like it is in the movie.

Both leads put in stellar performances, and are perfectly cast in their roles. Ali looks a shoo-in to get the Best Supporting Actor Oscar, two years after he won in the same category for Moonlight.

Like many films apparently based on a true story, the lines appear to have been blurred here, with Don's family refuting much of the storyline. However, as a stand-alone piece of cinema, Green Book is a truly enjoyable watch and one that will have you laughing, clapping and maybe even shedding a tear or two.