If you love Oasis, you'll love the new documentary.

"I hate the term sibling rivalry, but that's what it is. I know my brother better than anybody else and Liam is like a dog, and I'm like a cat. Cats are very independent creatures - they don't give a fuck, right bastards - and dogs are just like 'play with me, play with me, please throw that fucking ball.' It's as basic as that. You can't change the way that you are. I'm a cat, that's just what I am. I've accepted it, I'm a bit of a bastard." - Noel Gallagher in Supersonic. Aside from the incredible story of Oasis and their breathtaking back catalogue of tunes, a large reason why Mat Whitecross' brilliant documentary, Supersonic, worked is because it captured the love/hate/love/hate/hate/hate/love relationship between Liam and Noel Gallagher. In terms of the origin of their rivalry, both men will happily recall a time when Liam stumbled home drunk and continued to piss all over Noel's new stereo as the moment it began, but the truth is actually far more normal and mundane. Isn't that what family life is like? In his own words, Noel always resented Liam because he was younger, more charismatic, had a better walk, and clothes always looked better on him. As for Liam, he had a chip on his shoulder because Noel was the talented musician, a far better songwriter, and a more natural leader for the band. We all know the history of their fights, but in the new documentary Liam Gallagher: As It Was, viewers will get a very different look at the world's most famous Parka-wearing singer. Without giving too much away, the new film documents the fall and rise of Liam Gallagher as he goes from the dizzying heights of Oasis to the lows of being ostracised from the music industry. Make no mistake about it, this is very much Liam's story as we get to see a side of his personality that's rarely seen. Granted, the hilarious bravado and one-liners are still there - Liam will always be addictive company - but it's the more somber moments that really resonate. We see Liam hurting. We see Liam worry over the future. We see Liam dealing with the most normal issue that we all experience - anxiety. This is Liam's story but so much of his life revolves around Noel. Similarly, so much of Noel's story revolves around Liam. Oasis fans will know that the brothers still aren't talking to each other - despite the interventions of their saintlike mother from Mayo, Peggy - but when it came to making the documentary, this posed a real problem for its co-director, Gavin Fitzgerald. Ahead of the documentary being released, JOE had the chance to chat with Fitzgerald and we had to ask him about the elephant in the room. In terms of its narrative approach, the documentary starts with that infamous gig in Paris and the breakup of Oasis, however, would Noel and the breakup of Oasis be a touchy subject for the singer to talk about? Fitzgerald says that when it comes to Liam Gallagher, nothing is off limits. “Liam was pretty open doing the interview. He actually had no problem talking about Noel and whenever I’d bring it up (the breakup) while filming, I’d be cautious about it because I didn't want to bring up bad feelings in him, but he’s like ‘well I’m always bringing him up!’ so that was his way of giving me permission.

"I think that’s where the story needed to start (the breakup of Oasis). Supersonic was a great film and it charted the rise of Oasis, but this film is very different in that it’s Liam’s story. Liam’s story really starts when Oasis split up because he’s out on his own for the first time. He is a creative singer and he had to prove that, but it’s not easy when you’re just known as the singer of Oasis. That’s where it starts for me."

Supersonic featured some blistering Oasis songs - the live tracks and unheard recordings from the studio were exceptional - but Liam Gallagher: As It Was is very different as it features no Oasis tunes.

This isn't for the want of trying, though.

"When I came onto the documentary at a later stage of production, we were under the impression that we could use Oasis music. But Noel owns the publishing rights to all of that music so if he refuses, you can’t use any Oasis songs," said Fitzgerald.

"Then we thought we could use songs that Liam had written and performed for Oasis, but Noel strummed a guitar on those tracks too and he refused those songs also. It’s a little bitter, maybe it’s his way of getting back at Liam for the stuff that he says about him," added the director.

Despite these setbacks, Fitzgerald did reach out to Noel by asking him to feature in the documentary. Sadly, the request fell on deaf ears.

"You’re hearing more from the lawyers about that one but they said no. Obviously, I’d have loved to have Noel in the documentary and hear his side of the story but he wasn’t that interested. There’s no big Oasis angle in this documentary and we were focusing more on Liam's story, but Noel is a very big part of that.

“There’s a couple of things that proved to be tricky. Using any footage of Noel had to be acquired by a third-party and that proved to be very expensive. Creatively, we were restricted in that way. In terms of the narrative approach, I felt that Liam should carry the film but of course, Noel is the elephant in the room and you need to address it."

At present, both men are enjoying an incredibly successful period in their solo careers - Liam is about to record his second album while Noel's latest record, Who Built The Moon?, received a Mercury Award nomination - but would an Oasis reunion ever happen? Having spent more time with the singer than most other people, Fitzgerald isn't that optimistic but he does think that Liam misses his big brother.

"I think Liam says outrageous stuff about Noel - usually when he’s angry - and he’s a bundle of emotions when you mention Noel, but at the heart of it, I think he does miss him. I think Liam would get Oasis back in a heartbeat but I don’t think Noel would ever do it. I don’t see him going back there to that place. I can’t see him (Noel) being the back up singer because he’s a frontman now and he's running things in his own circles. They’re very different people now and they're at very different times in their life."

Thankfully, we're delighted to say that the documentary isn't any weaker, less captivating, or engaging without Noel. If you loved Supersonic, Liam Gallagher: As It Was does feel like its spiritual sequel while also having its own identity. Just like the Gallagher brothers, eh? Somewhere, right now, we reckon that Noel Gallagher is probably thinking about making his own documentary, just to one-up Liam. We wouldn't have it any other way. Liam Gallagher: As It Was is released in Irish cinemas from 7 June. Here's a taste of what's in store. https://www.youtube.com/watch?v=aPPw18Psnj0& Clip via Altitude Films