The former Oasis star played guitar and sang along with Damon Albarn's animated band and fellow collaborators Blur's Graham and Savages' Jehnny for a rendition of their song 'We Got The Power' at the London arena on Monday night (04.12.17), putting to bed any past feuds the former Britpop rivals might have had.
Happy Mondays singer Shaun Ryder also came on stage with singer Roses Gabor to perform 'DARE', the 2005 song from 'Demon Dayz'.
And the star-studded bill didn't stop there as rapper Vince Staples, Pusha T, De La Soul, Mos Def, Bootie Brown, Gruff Rhys, Pauline Black and D.R.A.M. all got to join in the 'Humanz' fun, by performing their respective tracks from the critically-acclaimed record.
One of the highlights of the night included Little Simz' stripped back vocals on 'Garage Palace', the surprise song which was released after the album came out.
Meanwhile, Albarn, 49, previously gushed about how ''great'' Gallagher, 50, was in the studio recording the track.
He said: ''He's really great. He's fantastic in the studio, you know, and it's nice when you see how someone goes about their business, you know, and he's great ... There wasn't any ice to break, no.''
Asked if he contributed to the record or just did as he was asked, he added: ''Well, I mean ... it's not orders, it's more like kind of this is, you know, we agreed that this was how we were going to approach it.''
Gorillaz' The O2 tracklisting was as follows:
'Last Living Souls'
'Tomorrow Comes Today'
'Every Planet We Reach Is Dead'
'Charger' (with Pauline Black)
'Superfast Jellyfish' (with Gruff Rhys and De La Soul)
'On Melancholy Hill'
'Intro: I Switched My Robot Off'
'Ascension' (with Vince Staples)
'Strobelite' (with Peven Everett)
'Interlude: Elevator Going Up'
'Andromeda' (with D.R.A.M.)
'Sex Murder Party' (with Jamie Principle and Zebra Katz)
'Sweepstakes' (with Mos Def and Hypnotic Brass Ensemble)
'Garage Palace' (with Little Simz)
'Broken' (with Hypnotic Brass Ensemble)
'Let Me Out' (with Pusha T)
'Dirty Harry' (with Bootie Brown)
'Stylo' (with Mos Def and Peven Everett)
'Feel Good Inc.' (with De La Soul)
'We Got the Power' (with Jehnny Beth, Noel Gallagher and Graham Coxon)
'Kids With Guns'
'DARE' (with Shaun Ryder and Roses Gabor)
'Don't Get Lost in Heaven'