The 57-year-old has been cast in David E. Talbert's Christmas tale, about a cobblestone world that comes to life.
According to Deadline, he'll play Jeronicus Jangle, a once-great inventor and toy maker who has lost his belief in himself and his inventions, but stumbles upon a second chance and a magical invention, when his granddaughter comes to town for the holidays. It's slated for a 2020 release.
This isn't the first time Forest has shown off his musical skills; in 2013 he starred in "Black Nativity" opposite musical heavyweights Jennifer Hudson and Mary J. Blige. He's also displayed his impressive vocal abilities on TV show "Empire".
Prior to his acting career, Forest studied singing at university, after changing his course - a football scholarship - following a back injury. He even toured England with the Cal Poly Chamber Singers.
Talking about his last foray into a musical, the star said it was intimidating to perform alongside his co-stars.
"Looking back, the last scene we did was the most daunting, with Jennifer, because she is such an amazing singer," he told The Daily Star. "We had recorded it, so I knew I could just mouth it if I got too nervous. But they wanted to do it without the recording; they wanted it live, so that was a little more daunting. By that point, though, I was so into the character it worked out. I was so consumed by who he was and I was connecting to the audience in my church and my choir, so I was able to bypass that."