The 52-year-old outspoken British television personality previously slammed the 'Problem' hitmaker for flying back to the US immediately after the atrocity, but took to Twitter on Sunday (04.06.17) night to apologise to the star after she organised a benefit concert in the English city.
The One Love Manchester concert was held at the Emirates Old Trafford cricket ground and broadcast around the world, with all net profits from the event going to the We Love Manchester Emergency Fund set up to help those affected by the attack.
Piers wrote on Twitter: ''I thought Ariana Grande was wrong to fly off after #ManchesterAttack. But tonight she's putting on a fabulous show. #OneLoveManchester
''I'll say this too about @ArianaGrande - she has a cracking voice. By far the best vocal performance tonight... #OneLoveManchester
''2 weeks after ISIS bomb a pop concert, a bigger & better one's held in same city. What better way to say F**K YOU? #OneLoveManchester
''I misjudged you, @ArianaGrande & I apologise. You're an admirable young woman & this is a magnificent night. Respect.#OneLoveManchester (sic)''
Whilst on stage at the music extravaganza, the 'Side to Side' singer took a moment to speak to the 50,000 strong crowd at the venue - 14,000 of whom were at the singer's show when the attack took place - to thank them for being the ''medicine that the world really needs right now.''
She said: ''Before we go any further, I want to thank you all from the bottom of my heart for being here today. I love you so so much. Thank you. I want to thank you so much for coming together and being so loving and strong and unified. I love you guys so much and I think that the kind of love and unity we're displaying is the medicine that the world really needs right now. So I want to thank you for being just that.''
Ariana was joined by Black Eyed Peas, Robbie Williams, Take That, Justin Bieber, Coldplay, Niall Horan, Miley Cyrus, Katy Perry, Pharrell Williams, and Little Mix at the event, where fans were also treated to a surprise appearance from Manchester's own Liam Gallagher.