Liam Gallagher was ''lost'' after his band Beady Eye split and it was his girlfriend Debbie Gwyther who ''saved'' him, 'As It Was' documentary maker Charlie Lightening has claimed.

Lightening has captured the rock 'n' roll legend both on stage and off stage for the upcoming film which focuses on Liam launching a solo career in 2017 with the release of his album 'As You Were'.

The filmmaker has revealed that the doc shows just how important Debbie - who he met after she started managing his band Beady Eye before they split in 2014 - is to Liam and how she pulled him out of his creative slump and gave him the confidence to move on from Oasis and start anew.

Speaking to digital publication GQ Hype, Lightening said: ''Oh, Debbie's impact was massive. She saved him in so many ways. He was lost. He didn't know what to do or how to do it. As he say in the film she gives him a kick up the arse, explains that, 'Come on, no one died,' and tells him to focus again on the music.

''She supported him through some of the worst. And they just love each other, you know what I mean? It's all in the film. You see how close their relationship is, how they bring out the best of one another. Again, it feels wonderful that I was able to capture that, as really I was doing his musical comeback, I wasn't doing a documentary about Liam's love life, but then Debbie is such a part of that, and now his family, that it shines through - hopefully.''

Lightening admits the presence of Liam's estranged brother and former Oasis bandmate Noel Gallagher looms large over the film and how that fractured relationship affects the 'Wall of Glass' singer.

He added: ''There's still those questions and still that relationship that is there or not there. At the end, the keyboard player, I think, says, 'I think Noel overestimates the importance of the music and underestimates the importance of Liam.' And he makes the point that, 'I am sure [Liam] can't do anything without wondering what his brother thinks of it. Everything he leaves out or puts into a show is almost solely done for an audience of one.' The Noel questions are there, of course, but they don't dominate. As Liam says, 'Noel has become a massive ****. Whereas I'm just still a ****.' ''