The Angry Mob singers performed at London's O2 Arena on 5 November as part of their current UK tour and ticketholders complained on social media that Wilson had slurred, forgotten lyrics and told the crowd repeatedly he didn't want to be there.
Wilson, 44, said in a statement to The Sun: “I don’t want to make any lame excuses, I’ve met some challenges in this life I’ve led, and stayed on top of them with the support I’ve always had around me.
“The truth is I made a mistake on Saturday night at the O2, and relied on old drinking habits, it’s a mistake that upset and disappointed many of you, and some of those closest to me.
“I try to take pride in not letting people down and seem to have let myself down in that respect the other night. I’m doing everything that is necessary for me not to let that happen again. And will continue to.”
The I Predict A Riot singer was a judge on singing talent show The Voice for three series from 2014 to 2016.
The Kaiser Chiefs formed in Leeds in 2000. Their last album was released in 2019.
They are currently on their All Together tour of the UK.
Following the show at the O2 Arena fans complained about Wilson's performance on Twitter.
One ticketholder said: “Real talk: is Ricky Wilson okay??? Either he was completely off his nut on something throughout tonight’s Kaiser Chiefs show, or he’s got some really worrying behaviour going on. It was kind of uncomfortable to watch.”
Another who was at the venue tweeted: "Ricky Wilson was absolutely wasted. Slurring, forgetting lyrics, stumbling all over the place, repeatedly telling the crowd that he didn’t want to be there. Never seen an arena empty out early, so quickly!"
Several fans also called on the band to offer an apology or a refund for the standard of performance.
Some fans also said they were sending Wilson support if he was going through any issues, with one saying: "Kaiser Chiefs anything to say about last-night? EVEN an apology for what we had to endure. We all support you and are fans but this followed by Ricky announcing he didn’t even want to be there was not great. I just pray whatever was wrong with Ricky he is ok now."