“Green Book” is a legitimate Oscar contender, and probably will be nominated for Best Actor for Viggo Mortensen. I give “Green Book” 3.5 stars out of four.

Mortensen did all the requisite things you’re supposed to do to get Best Actor. He gained about 70 pounds for this part, and you don’t recognize him. This is not one of those roles where he plays a charismatic, dashing leading man.

He’s an overweight guy who loves to eat, and who basically is hired as a driver/bodyguard for this historic music figure Dr. Don Shirley, who many haven’t heard of. But when you go back and listen to his music, you see that he was an amazing guy. He played with the Chicago Symphony, he played with the Boston Symphony and the Boston Pops many times. He concertized through Europe as a classical pianist.

This is set in 1961-62 and it’s like “Driving Miss Daisy” in reverse. The elegant, aristocratic, extraordinarily well-educated Shirley had three PHDs, one in Liturgical Studies, one in music and one in psychology–he was also a practicing, licensed psychologist.

An unbelievable guy, he was a tremendous hit as a musician, playing a kind of classical accented jazz that was very popular in the early sixties. The problem is that he was insistent — as the movie makes clear, for reasons that go way beyond making money — in concertizing in the South.

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And while there were a lot of places in the South that were perfectly eager to have this famous musician come and play there — in Birmingham, and Mississippi, and Georgia — at those same places he couldn’t go into restaurants, he couldn’t stay at regular hotels, as there were separate hotels for black people.

The “Green Book” from the title was a travel guide that was written for black people at the time, which would tell them where they had to go in the South if they wanted to eat or find a place to sleep at night.

The film is fascinating. It’s almost entirely a surprise because it’s directed by Peter Farrelly of the Farrelly brothers, who are previously known by “There’s Something About Mary”, “Shallow Hal”, and “Dumb and Dumber”, silly comedies with a romantic heart. This has comedic moments, but it’s a very serious film, and with two of the best performances of the year.

Don Shirley is played by Mahershala Ali, who won an Oscar already and may get a second one for this. He won an Oscar for Supporting Actor in “Moonlight”, and he captures Don Shirley with such extraordinary force.

It’s one of the better films of the year, and a huge triumph for the all the acting.