Elle King has admitted to having had "one shot too many" before her "awful" Dolly Parton tribute performance.

The country singer explained she had been drinking cocktails and tequila shots before going on stage to perform at a tribute concert to honour Dolly Parton's 70th birthday earlier this year.

"I played two shows that day. I played two f**king shows. The first show was great. It was perfect," Elle, 36, told Bunnie XO on the Dumb Blonde podcast. "But I hadn't eaten ... I hadn't slept in days. Had such bad anxiety."

On stage in January for the birthday tribute, Elle was seen slurring her words, swearing at the audience after some demanded a refund, shouting "You ain't getting your money back!" and forgetting song lyrics before show organisers dropped the curtain.

The Exes and Ohs singer reflected on the incident and explained she had "taken one shot too many" after visiting a bar before the show.

"I took one shot of tequila when I had been drinking a martini," Elle explained, adding she was also "the tiniest I'd ever been".

In February, Dolly, 79, offered her support to Elle in the wake of her trainwreck appearance.

"Elle is really a great artist," Dolly told Extra. "She's a great girl, and she's been going through a lot of hard things lately.

"She just had a little too much to drink, so let's just forgive that and forget it and move on, 'cause she felt worse than anyone ever could."