The singer was a shock addition to the line-up, taking to the stage to perform classic Oasis hit ‘Rock N Roll Star’.
He also dedicated ‘Live Forever’ to the victims of the Manchester bombing, which killed 22 people when a suicide bomber detonated a nail bomb at an Ariana Grande concert at Manchester Arena last month.
Event organiser Ariana had promised fans a surprise throughout the concert, which took place at the Emirates Old Trafford cricket ground.
And as the show came to a close, it was revealed Liam was the shock performer. However, there was no sign of his brother and former Oasis bandmate Noel, who skipped the chance to reunite the group.
As well as performing the Oasis classics, Liam also sang a rendition of one of his solo songs, ‘Wall Of Glass’.
As the group offered their take on the Oasis song, its lyrics took on a new, poignant meaning in the wake of the Manchester bombing, which killed 22 people at an Ariana Grande concert last month.
Other acts who performed included Justin Bieber, Katy Perry, Miley Cyrus, Robbie Williams and Little Mix.
All net ticket proceeds will go towards the We Love Manchester Emergency Fund set up by Manchester City Council in partnership with the British Red Cross.
To donate £5 to the We Love Manchester fund, text LOVE to 70507. Texts cost £5 plus your standard network rate, with 100% of your donation going to the We Love Manchester fund.