Why did Willie Nelson abruptly walk off the stage during his Charlotte show?

CHARLOTTE, NC (Theoden Janes/The Charlotte Observer) - Country Music Hall of Famer Willie Nelson came to Charlotte's PNC Music Pavilion on Saturday night specifically to headline his Outlaw Music Festival, then left without ever playing or singing a single note - leaving fans confused, angry and disappointed.

Live Nation issued a press release after 11 p.m. Saturday night, saying, simply: "Due to illness, Willie Nelson was unable to play tonight at the Outlaw Music Festival at PNC Music Pavilion Charlotte. Fans are asked to please hold on to their tickets until the new date is announced."

In a video posted Saturday night by a YouTube user named Michael Keim, the 85-year-old Nelson can be shown shuffling slowly onto the stage, picking up a guitar, setting the guitar back down, curtly whipping his cowboy hat into the crowd, then shuffling back off-stage.

The caption on Keim's video noted, as have others, that he came out and walked off twice.

Multiple concertgoers reported on Twitter that they then stood around for an hour before they were told that Nelson would not be coming back and that the show was over.

It's been a rough year for Nelson. He also canceled multiple concerts in February due to the flu, although — fortunately for fans in those cities — he made the call well in advance.

Whatever the case may have been, Nelson's abrupt departure was the most significant of a number of significant blows to the festival, which in April saw Elvis Costello withdraw due to "a non life-threatening surgical procedure" and two weeks ago saw Brandi Carlile bow out "due to unexpected family obligations overseas."

In the end, fans heard sets from alt-country innovator Sturgill Simpson, Americana string band Old Crow Medicine Show, and add-on performers Wild Feathers and Mitchell Lee, then got a couple of glimpses of Willie Nelson, and did a whole lot of standing around.

This story will be updated when a makeup date is announced, or if more information about Nelson's ailment is disseminated...