Barnes drove for four hours to get to Bella, near Beauly in the Highlands, and arrived 10 minutes before he was due to go on stage.
“The security guard at the front of Belladrum wouldn’t let me in. I said: ‘I’m playing the main stage’, but she said my name wasn’t on the list.
“I drove past her. I felt awful, she was running after the car.”
Returning to Glasgow on Sunday, Barnes finished his “mad weekend” in style performing with Delta Goodrem, who had hits in the early 2000s including Born to Try and Innocent Eyes.
“That was a crazy experience,” said Barnes. It was the first time I’ve worn a suit on stage, which was cool.”
He added: “She was so, so nice. She’s an absolute Australian superstar, so it was fun for me to get the opportunity to do that with her.”
Barnes said he was living a dream he had held since his first gig when he was 16.
“I’m 36 now. It has taken me 20 years to get to playing the main stage of festivals.
“Twenty years of absolute hustle, of not selling gigs.
“Most normal people would have quit and done something else.”