Marr plays on the former Oasis guitarist's upcoming single Ballad of the Mighty I, and Gallagher has revealed his pal insisted on recording his part 'blind' by not listening to the track first.
Gallagher was left awestruck by Marr's technical ability in the studio, and he has hailed the rocker as the best of his generation.
He says, "I tried to get him to play on the last album but it never happened. So when I put this track together and knew he would be perfect for it I called him and asked if I could send him the rough mix. He said: 'No, I don't want to hear it. I'm just going to react to it on the day.' He didn't even want any pointers.
"Well, that was brave of him. He just arrived with two guitars and a bag of effects pedals. And I have to say, he's unbelievable. He's way up there, on another level to the rest of us. The result is a burst of energy that helped make Mighty I one of the best songs I've ever written."