Zayn Malik pulled out of the Capital FM Summertime Ball on Saturday citing "anxiety" and posted an apology in his full explanation on his official Instagram account.
He said: "To all those people who have been waiting to see me perform at the Capital Summertime Ball today ... I flew into the UK last night to appear in my home country in front of my family, friends, and most importantly my UK fans.
"Unfortunately my anxiety that has haunted me throughout the last few months around live performances has gotten the better of me ... with the magnitude of the event, I have suffered the worst anxiety of my career."
He added: "I cannot apologise enough, but I want to be honest with everyone who has patiently waited to see me, I promise I will do my best to make this up to everybody I've let down today.
"I know those who suffer anxiety will understand and I hope those who don't can empathise with my situation."
Fans who have an opinion have been sharing their thoughts on Twitter.