Still a work-in-progress, the film follows the band’s strict Pentecostal upbringing under their evangelist father and worship leader mother to their fallout with faith and new lifestyle of drugs, sex, and rock n’ roll.

The trailer reveals home videos of the Followill brothers (and cousin) during their travels across the South, where a majority of their youth was spent, showcasing believers being healed, speaking in tongues, and being overcome by the Spirit or devil, contrasted directly with band members guzzling whiskey, smoking, yelling at each other and of course, vomiting.

In the opening of the trailer, one of the band members voices, “As soon as I knew we got a record deal, that whole night I never slept because I knew I was going to hell and I wasn’t going to be a preacher.”

Their father, Ivan Leon Followill, comments on his boys’ newfound stardom, telling the camera, “I don’t want to say my kids are going to hell you know, nothing like that, but as far as what I envisioned, it’s a little different.”

The word “little” appears to be an understatement, as the majority of the Followill childhood was immersed in attending church services, tent revivals, and homeschool sessions.

No movies, no other music but church music, no mixed bathing, no competitive sports, and no short pants comprised a few of the rules within their home, Rolling Stone reported.

Attending a preachers’ conference with their father was about as exciting as it got for the Followills.

Jared, the youngest brother of the band and bassist, even went to say in the trailer, “I always felt like we were the Christians and everybody else were sinners.”

So what exactly was it that set off the difference their father sees in his children and nephew now? Apparently, his own fallout with God.

In 1997, their well-respected father, after much struggle with alcohol, divorced his wife and subsequently resigned from the church, leaving his sons completely disillusioned.

“Our parents’ divorce shattered the whole mirage of this perfect little existence the outside world couldn’t touch and couldn’t pollute,” Nathan, the oldest Followill brother, told the magazine.

“We realised that our dad, the greatest man we ever knew, in our eyes, was only human. And so are we … this whole new world was open to us.”

Meanwhile Caleb, lead vocals and guitarist, told The Independent, “I’d put my faith in my dad and I wanted to follow in his footsteps. I’d always look up to ministers, but at about fifteen I started to see that they were just normal men and it broke my heart. I closed myself off to pretty much everyone and dropped out of school.”

Nathan and Caleb relocated to Nashville soon after and began embracing a new lifestyle, finding comfort in songwriting. Six months later, the two brothers were signed with a record company, asking their youngest brother Jared and cousin Matthew to join their band.

And the Kings of Leon were born, named after their grandfather and father.

Though much of their life is radically different now, the brothers admit that there are still remnants of their religious upbringing left within them and attribute who they are today to their background.

“We realise now looking back on it that the way we were raised definitely shaped us into the guys that we are. There are definitely things from that time of life that I want to keep, especially being a good person and being thankful for everything that you have,” Nathan shared to Relevant Magazine.

Nathan expressed that they believed in God, still gave money to churches, attended service every now and then, and that he said his prayers every night before he went to bed.

“We’re no saints, by no means,” he told Pure Music. “[But] I like to think we’re good people and have good hearts.”

Caleb, who still wonders whether he should become a preacher at times, confessed, “To be a man means that you are born into sin, so you might as well be honest about it.”

He told The Independent, “Look at David in the Old Testament. He was a man after God’s own heart, yet he plotted the death of one of his generals so that he could marry the guy’s wife Bathsheba.

“So if he’s the man after God’s own heart, well, maybe when you’re at your roughest moment, that’s when He’s watching over you and smiling.”

Their song “On Call” resonates this similar biblical theme. The lyrics read “And when I fall to pieces, Lord you know I’ll be there waiting.”

So is there some kind of message that the brothers are trying to relay with this new documentary?

Are they trying to justify their lifestyle now by revealing a religious aspect of their past? Or do they want to show fans that they are simply just as confused as the rest, unable to reconcile their faith?

Perhaps there’s no message at all. It could just as well be another rock n’ roll film about four modest boys who grew to be not so modest after all.

Whatever it is or isn’t, it appears as if the Followill family is still a work-in-progress indeed, just like their new film.

The Tribeca Film Festival starts April 20 and runs until May 1.