Milo Ventimiglia Sings in Inspiring ‘I Can Only Imagine 2’ Trailer (Exclusive)

Bart Millard’s inspiring true story continues in theaters this winter.

PEOPLE has the exclusive first trailer for I Can Only Imagine 2, and in it Bart (John Michael Finley) meets Tim Timmons (Milo Ventimiglia), a singer-songwriter who seeks to uplift others even as he fights his own battles.

According to a synopsis, “After the breakout success of the song ‘I Can Only Imagine,’ MercyMe’s Bart Millard is living the dream: sold-out arenas, a devoted fan base and a thriving career. But behind the spotlight, Bart’s past threatens the family he’s built, especially the fragile bond with his son Sam (Sammy Dell).”

Enter Tim as a “hopeful newcomer” who joins the band ahead of their “biggest tour yet” and “unknowingly brings a renewed gratitude to Bart’s life through their unlikely friendship.”

“Bart soon discovers that Tim carries hardships — and secrets — of his own, forcing him to face his past and repair his relationships with Sam and his wife Shannon (Sophie Skelton) before fame costs him what matters most,” the synopsis adds.

Ventimiglia tells PEOPLE the real Timmons played an integral role behind-the-scenes of the film. Timmons, 49, was diagnosed with cancer over 20 years ago. At the time, he was given five years to live, but he continues to defy the odds and share his story through ministry and song.

“Tim and I spent a ton of time [together], and he was on set every day,” says Ventimiglia, 48. “The nice part about the whole filming experience was I met now one of my very good friends for the rest of my life.”

He adds, “But what drew me to the role was this man who had been given a sentence of cancer and had still put a lot of positivity out in the world, although he was battling and dealing with something so daunting and terrifying.”

In the trailer, MercyMe lead singer Bart once again finds himself struggling personally even as the band continues to reach new heights of success.

“You got your dream, you inspired millions of people — what’d you think was going to happen? You were just going to ride off into the sunset? No more struggles or pain?” Trace Adkins’ Scott Brickel asks as scenes of the band’s rise are juxtaposed with Bart facing his personal demons.

Since the sequel is based on the creative process behind MercyMe’s song “Even If,” Ventimiglia had to dive into the musical aspect of the role, which he says proved to be the most “challenging” part of filming.

“The biggest challenge really was, for me, making sure that the performance looked correct,” he says. “I mean Tim’s been playing music since he was young, and we’re the same age, in our late 40s. To be able to look like I’m onstage and jamming the way that Tim jams and singing the way that Tim sings, it was a lot of effort. But it was also a ton of fun.”

The This Is Us alum adds, “I realized I didn’t have to learn how to play guitar entirely, I just had to learn how to play three songs really well. Tim taught me like seven or eight different ways to play those songs.”

Ventimiglia says he and the rest of the cast also felt a sense of responsibility in terms of ensuring that they captured the essence of the real people they were embodying in the film.

“These are real people with real lives, and it’s not a movie for them. This is their life,” he says. “So for me, the artist, and for Andy Erwin and Brent McCorkle, the writer-directors, what we have to do is respectfully tell this story and make sure we’re honoring these people in a way that they want to be represented.”

McCorkle says returning for the sequel, which also stars Arielle Kebbel, Sammy Dell and Dennis Quaid, “has been a deeply personal and profoundly moving journey — for me and for so many who helped bring this uplifting story to life.”

“Its themes of finding gratitude in our grief and discovering beauty that rises from ashes feel more relevant now than ever,” says McCorkle. “Watching this chapter of Bart and Tim’s story unfold for the big screen has been an honor.”

Erwin adds, “I Can Only Imagine was such a defining moment seven years ago. I never dreamed there was more story to tell — until we heard the story behind MercyMe’s hit ‘Even If.’ Learning how Tim Timmons and Bart Millard co-wrote that song out of deep lived-faith moved us to tears.”

“The honesty and hope woven through each of their journeys is undeniable,” says Erwin. “Brent and I knew immediately that I Can Only Imagine truly deserved a sequel.”

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Ventimiglia wants people to leave the theater “not being so weighed down” by “all the struggles that we have in life, all the things that we individually and collectively go through.”

Instead, he hopes the film’s message of “finding goodness, finding compassion, finding friendship and love, and being able to give those things” will resonate with viewers.

“I hope a film like this can show that to people, and they can take that and put that practice into their own lives,” he adds.

I Can Only Imagine 2 is in theaters Feb. 20.