When a man loves a city, he’s got to make a movie about it. At least that’s the case for Michael Bolton, whose latest passion project is a documentary about Detroit and its potential for resurgence.

The Grammy-winning singer has been spreading an excess of good cheer in his hip new holiday commercials for Honda. But that’s nothing compared to his feelings for the Motor City.

“We are in love with the people we have met in Detroit,” he said. “It’s literally turned into a lovefest.”

Over the past four decades, Bolton has sold more than 50 million albums and singles worldwide. His lengthy career as a singer has spanned the sincerity of his chart-topping ballads like “Love Is a Wonderful Thing” and the self-parody of his guest role as Captain Jack Sparrow in a well-known “Saturday Night Live” digital short by Andy Samberg’s the Lonely Planet group.

But during a recent phone interview, the 60-year-old crooner doesn’t want to talk about his hits. He’d rather focus on the documentary that he hopes will spread the message that Detroit is poised for a comeback.

Where others see a bankrupt city on its knees, he sees a city where the entrepreneurial spirit is thriving, particularly real estate mogul Dan Gilbert’s revitalization plans.

Bolton’s project arose from his 2013 album, “Ain’t No Mountain High Enough: A Tribute To Hitsville, U.S.A.,” which came out in February. A love letter to the Motown music he’s loved since he was a kid of 9 or 10 growing up in Connecticut, it contains classics from the Detroit-grown empire like “Tracks of My Tears” and “Nowhere to Run.”

“All the feel-good the country needed was coming out of Detroit,” he said of the Motown era.

Bolton and his production company team had planned to make a video about Hitsville USA as a companion to the album. But after getting permission to shoot at the Motown Museum on West Grand Boulevard, they started getting phone calls “about this building that’s going on in the center of Detroit and a guy named Dan Gilbert and Quicken Loans.”

As Bolton explains, the focus of the project shifted to the entire city as he and his manager and executive producer of the film, Christina Kline, became captivated with Gilbert’s plans to revive the downtown area and spread the progress outward.

He was given access to film behind the scenes with Gilbert. “We went up to the planning rooms. We saw the walls full of stores they’re planning, the restaurants they’re planning, how many square feet. Everything had been taken into consideration, the demographic, the appeal of downtown.”

On the day of his phone interview, Bolton was preparing to see a 90-minute version of hundreds of hours of footage shot during several trips to Detroit. In addition to the time spent with Gilbert and his brain trust, that footage includes “a fascinating interview” with Aretha Franklin as well as moments like Bolton performing live with Smokey Robinson and talking to other music luminaries.

As a producer and executive producer of the project. Bolton says he’s had a hands-on role, making at least four trips to Detroit for filming. “It’s been much more in-depth than I originally intended, but I’m grateful for that.”