Hugh Jackman and Kate Hudson chase a dream in ‘Song Sung Blue’

Hugh Jackman never thought he’d be a karaoke guy. But then Neil Diamond happened.

Starring opposite Kate Hudson in the Christmas Day release “Song Sung Blue,” the 57-year-old Australian actor portrays not the legendary Grammy winner and shaggy-haired sex symbol, but rather a Neil Diamond “interpreter,” the real-life Mike Sardina, who, with his wife and stage partner, Claire (Hudson), found unexpected success with a tribute band in mid-1990s Milwaukee.

It was this film that recently brought the “Greatest Showman” star to Diamond’s Colorado ranch, where the two participated in a singing session that convinced Jackman to buy his own karaoke machine.

“Normally, I’m like, ‘I don’t want to do that,’” says Jackman, over Zoom from a New York hotel room, as if he’s confessing a mortal sin. “But I did karaoke with Neil, and I’m like, ‘All right, now I’m in.’”

What did they sing? Diamond soloed on “I Dreamed a Dream” from “Les Misérables,” paying tribute to Jackman’s musical theater bona fides, before the two duetted on Elvis Presley’s “Can’t Help Falling in Love” and, of course, Diamond’s own “Sweet Caroline.” The good times never seemed so good.

It was a hang session so epic that Hudson, joining the call, seems green with an envy that matches her sweater. “I can’t believe I missed this karaoke party,” she says. “I have a whole karaoke setup at my house with a microphone and everything. I feel very left out.”

Thankfully, when it came to making “Song Sung Blue,” it didn’t seem so lonely for her. Based on Greg Kohs’ 2008 documentary of the same name, the film is as much Claire’s tale as it is Mike’s, following the real couple’s love story set to the tune of Diamond’s extensive songbook. At the height of their success, which included playing with Pearl Jam at Eddie Vedder’s request, the Sardinas became local celebrities, billed as the duo “Lightning & Thunder.”

A Vietnam vet and mechanic with a dream of entertaining, Sardina seems a role tailor-made for Jackman, who can go from Wolverine to Broadway in a single season. “Song Sung Blue” writer-director Craig Brewer, who first saw the documentary at a small film festival in Memphis, Tenn., never envisioned anyone but Jackman as the insatiable Wisconsinite.

“It was always Hugh because there’s not anybody else out there who could understand the wild showmanship that Mike Sardina had,” says Brewer, calling from his Memphis home. “He’s doing two layers of a character. He’s playing this working-class guy that loves to entertain any way he can. If he’s got to wear sequined shirts, he’s going to. He’s going to give you everything he has.”

The role presented a puzzle for Jackman, despite having played career impresarios like pop idol Peter Allen and P.T. Barnum. “I had to lose Hugh Jackman to be Mike,” says the actor, relaxed in an umber-colored button-down shirt. “How does Mike find himself within his love of Neil? It took me a second to find him and lose my shtick, because I’m a performer too.”

Ultimately, the solution wasn’t his Neil Diamond impersonation, though Brewer encouraged Jackman to make a meal of that. “You can lay a little bit more butter on it,” the director remembers telling him.

Instead, Jackman’s breakthrough came via deep self-identification.

“His dream was always huge but this was not how he thought it was going to go,” Jackman says. “It was that ‘one plus one equals three’ thing where, all of a sudden, they found themselves being the next big thing.” Similarly, Jackman never intended to become a movie star synonymous with musical theater. He’d never even sung before a post-university audition changed the course of his life.

Hudson is a less-obvious casting choice. Though she’s made a career playing rom-com heroines, with “Song Sung Blue,” she’s already generating awards buzz for her turn as a guileless Midwestern mom miles away from the glittering women Hudson typically portrays, and one with her fair share of trauma. She has to go to some dark places, channeling Claire’s depression, addiction to painkillers and more — but despite her penchant for playing more carefree women, Hudson says she wasn’t intimidated by the role’s meatier aspects.

“When you grow up with storytellers,” she says, referencing her actor parents Goldie Hawn and Kurt Russell, “you forget the camera’s there. You’re not thinking about anything glamorous. You’re looking at the role and what it needs. It’s what you long for as a performer. It allows you to almost leave your body.”

For Hudson, the opportunity also dovetailed with a new act in her own life as a recording artist. Even though she released her debut album “Glorious” only last year, Hudson has long identified as a singer-songwriter. “I was always so scared of it,” she confesses of her fear of going public about her songwriting. “But the studio is where I’m very happy. I’ve been in the studio since I was 19, but I just never shared my music because I was too scared to put it out.”

It was a discovery Jackman made while they were recording their vocal tracks for the film. “I said, ‘You’re a musician,’” he recalls, Hudson beaming at him. “You were so relaxed and in your home.”

“I’ve always had a lot of cheerleaders for me to do music,” Hudson replies, sheepishly.

Some might see it as a full circle moment for Hudson, who received an Oscar nomination for her performance as the groupie Penny Lane in Cameron Crowe’s 2000 rock memoir “Almost Famous.” It was such a formative experience that Hudson still remains close with Crowe. She tells me she’s reading his new book, “The Uncool,” to prepare to interview him on his tour.

But no matter how much Penny Lane has shaped her life, Hudson doesn’t see a through line from her to Claire. Instead, she draws a line between fandom and musicianship, specifically the distinction between those who chase the high of being in the room or backstage living the lifestyle, and those who have a song they have a visceral need to share.

“With Claire, it needs to come out,” she continues. “It doesn’t matter where or what we’re doing or how we’re doing it — we just need to do it. That is also how I feel about music.”

The real-life Claire Sardina and her two children (played by Ella Anderson and Hudson Hensley on-screen) threw their full support behind “Song Sung Blue.” But Hudson’s instinct was to build her own version of Claire without too much outside influence. “You want to make a choice in a film because it’s the right choice for the character, not because you’re trying to mimic something,” says Hudson.

That need to avoid mimicry and feel the moment was particularly crucial for the film’s heartbreaking second act, in which Claire is hit by a car in her front yard and loses a leg, plunging into self-loathing, depression, body dysmorphia and addiction. Hudson had to do extensive physical work to prepare to authentically represent Claire’s lived experience. “Movement is a huge part of what actors do,” she says. “There’s the emotional part but the physicality is like rebalancing your brain.”

In addition to watching YouTube videos of amputees and speaking with those in the disabled community, Hudson got useful advice from another screen legend — her dad.

“Kurt said that Claire is like Rocky,” she says, referring to the iconic character’s grit and determination to go the distance. “The part that really got my dad emotional was that she just wanted to figure out how to get on her feet.”

Jackman marvels at the bravery and skill of Hudson’s performance, noting that she even captured something the real Claire told him off-camera.

“Claire said, ‘The thing is Mike was a leg guy,’” he remembers. “Kate played that so well. That feeling of shame about: Is my partner attracted to me anymore? I found that incredibly moving.”

Hudson welcomed the challenge, but she did worry about one thing outside her control. For “Song Sung Blue” to work, the actors playing Claire and Mike need to be in perfect alignment: one the words, the other the tune.

“One of the hardest things to do is fake chemistry,” Hudson says. “You can’t do that. You have to actually fall in love with each other and find the chemical connection. That was my biggest anxiety.”

Jackman shared this concern. “I remember the first day after our table reading, you said, ‘This movie works if we work,’” he reminds her.

They needn’t have worried. “They were a net for each other as the other one was up on a tightrope,” Brewer says. “It was incredibly inspiring for the crew to see that kinship and respect.”

Their mutual generosity is evident in the way Jackman checks in with Hudson after each anecdote during our interview, confirming she has nothing to add or correct. Though this is their first film together, their repartee is so easy and warm it’s hard to believe they haven’t co-starred in at least a dozen movies.

“It felt easy to just inhabit these characters,” Jackman says. “The word that comes to me is trust. All of the scenes, particularly in that darker period, we could just live in that — the frustration, the paranoia, the anger, the loss, the fear. Every take felt really very different. I felt very free.”

Hudson agrees, adding with a giggle, “I told Hugh, ‘I’m really tactile. Just tell me if I make you uncomfortable. I’m going to kiss you all the time.’”

It helps that Hudson and Jackman are naturally sunny, curious people, celebrities who’ve never cared for the sound of being alone. “We like to connect with people,” Hudson says. “There’s no internal process that removes us. We’re both community people. We like to be in the circus. When we’re on set, we sit on set. There’s no separation of crew and cast. It’s very rare that you work with someone who is like that.”

Ultimately, that openness allowed Hudson and Jackman to approach Claire and Mike with honesty, essential for a film that’s a fullhearted paean to dreamers at their highest and lowest.

“Eddie Vedder told me something that moved me so much,” Jackman says, a note of emotion in his voice. “He goes, ‘Some might say these people led small lives. Their dreams were so huge and perhaps, naive. But dreams are so powerful that 30 years later, it’s come true.’”

From playing Milwaukee dive bars to becoming the subjects of a major motion picture, the Sardinas have far exceeded even their own expectations. To quote another beloved Diamond tune, it’s enough to make anyone a believer.