Elle King Suddenly Postpones Show, No Explanation After Dolly Parton Flub

Elle King will not be taking the stage later this week even though she was scheduled to -- 'cause she pulled the plug on her live gig kinda last minute ... without providing a reason.

The country star was set to rock the house Friday at a venue in Fort Worth, TX called Billy Bob's Texas -- which is basically a concert hall there in town ... and where EK was due to serve as the main talent heading into the weekend.

On Wednesday, however, it was announced by Billy Bob and co. that Elle would not actually be performing ... they said she had to postpone her show, and wouldn't be able to come back until way down the road in September.

TMZ confirmed the news -- and a rep there told us they just got word from Elle's team about this today ... so yes, the entire thing is very sudden. More importantly, we're told Elle's camp did not offer any valid explanation for the postponement.

While nobody has a clear answer on why Elle bailed, a lot of people are already speculating it may have to do with what went down over the weekend ... when Elle went onstage at the Grand Ole Opry and tried covering a Dolly Parton song -- only to botch it terribly.

She was accused of slurring her words, forgetting the lyrics and acting disorderly through the whole performance -- and many thought she might've been under the influence at the time. Elle herself confirmed that in her words ... telling everyone she was "f****** hammered."

Her "tribute" to DP caught a ton of flak ... and now, she's stepping away from the spotlight, it seems. We reached out to Elle's team ourselves and were told she had to postpone for "unforeseen circumstances" ... and they noted they wouldn't be commenting on this further.