Viggo Mortensen as Tony Vallelonga and Mahershala Ali as Dr. Donald Shirley in Green Book, directed by Peter Farrelly.

Filmed in New Orleans and nearby locations in southeast Louisiana, “Green Book” depicts a 1962 tour of the Deep South by African-American concert pianist Don Shirley.

A crowd-pleasing drama lightened by odd-couple comedy, the movie won the New Orleans Film Festival’s Audience Award last month. Its many prizes include the Toronto International Film Festival’s People’s Choice Award.

Mahershala Ali, an Oscar winner for 2016’s “Moonlight,” portrays Shirley. Viggo Mortensen co-stars as the elegant musician’s tough Italian-American driver and bodyguard, Tony Vallelonga. An awards season contender, “Green Book” opens nationwide Nov. 21.

“Something’s going on,” Mortensen said during a recent press day for the film. “This movie is striking a chord with audiences of all ages and backgrounds.”

Peter Farrelly, “Green Book” director and co-writer, attended the film’s festival screening in New Orleans.

“This is one of the highs of my life,” Farrelly said during a post-screening Q&A at the Orpheum Theater. “I plan to make good movies in the future, but I don’t know if I’ll ever make a movie that does this. You can’t plan this stuff. To be showing it down here, where we shot it, it’s a special night for us.”

Farrelly filmed one of the movie’s concert scenes in the Orpheum. Other New Orleans locations include the Roosevelt Hotel, McAlister Auditorium at Tulane University and the W.P. Brown Romanesque Revival mansion on St. Charles Avenue.

Darting to London, New Orleans, Los Angeles, Boston and Washington, D.C., in less than a week, Farrelly has made more promotional appearances for “Green Book” than for any of his previous movies.

“Crazy,” the director of “There’s Something About Mary” said by phone during the movie’s press day. “We don’t do anything like this for a regular movie. Normally, you’d have a press junket and a premiere. Then it’s over and you move on.”

Farrelly first heard the true story that became “Green Book” from actor-writer Brian Currie. A friend, Currie has appeared in some of the many comedies Farrelly wrote and directed with his brother, Bobby.

“I told Brian he should do it,” Farrelly said. “Brian said, ‘Yeah. It’s a home run.’ ”

After a few months passed, Farrelly phoned Currie to check on progress for the screenplay, a collaboration between Currie and Vallelonga’s son Nick.

“They hadn’t written a word,” Farrelly said. “So, I was like, ‘Can I write it with you? I love it.’ ”

The wide cultural divide between Shirley and Vallelonga grabbed Farrelly’s interest.

“They couldn’t be more of an odd couple,” he said. “Tony starts as a racist. But he goes on the road with this black concert pianist and they became lifelong friends. That’s what got me.”

Many things in the “Green Book” script appealed to Mortensen.

“Things that are difficult to put into one script,” the actor said. “And the movie makes you laugh, cry, think, feel. Every screening we’ve done, when the lights come up, the people are on their feet. People are, at least for a moment, different from when they came in that movie theater. And this has happened around the country, in Canada, in Europe, in London.”

Mortensen’s previous work includes “The Lord of the Rings” trilogy and his Oscar-nominated performances in 2007’s “Eastern Promises” and 2017’s “Captain Fantastic.” He gained 45 pounds to play Vallelonga, aka Tony Lip, a bouncer at the Copacabana nightclub who drives for Shirley when the Copa closes for renovations.

“It was easy and fun putting that weight on,” Mortensen admitted. “What better place than New Orleans to do that?” Prior to “Green Book,” the actor shot 2009’s “The Road” and 1996’s “Albino Alligator” here.

“I hate to go into Tony’s weight too much, because there’s a lot more to the character,” Mortensen said.

An actor who doesn’t have Italian heritage, Mortensen was initially reluctant to play Vallelonga.

“I was extra nervous with this guy,” he said. “I didn’t want to do a caricature. I wanted him to be a real person, real feelings. That’s my job as an actor.

“Once I started to get a feeling for the Vallelonga family, I could see it as possible. Because of the contrast between Tony and Don Shirley, I just needed to trust that difference. I needed to listen to Mahershala and take in anything he could give me. Because he is such a generous and detail-oriented actor, there was plenty to work with.”

Farrelly never doubted Mortensen could do it.

“I believe any great actor can do any role,” he said. “And Viggo is one of the best actors in the world.”

And having Mortensen aboard for “Green Book” helped bring Ali, who’d just won his “Moonlight” Oscar, to the project.

“Every actor wants to work with Viggo,” Farrelly said. “Mahershala was the first guy we went to. He and Viggo had just befriended each other on the awards circuit that year. They wanted to work together, so it timed out perfectly.”