AUSTIN, Texas (KTRK) -- Some Willie Nelson fans are seeing red after learning the country musician will be headlining a rally for Democratic Senate candidate Beto O'Rourke.Dozens of people weighed in on Willie's Facebook page Wednesday after he shared a story about the upcoming rally in Austin.While some people told Willie he needs to stay out of politics, others threw insults at the music legend. Still others applauded Willie's contribution to the 2018 campaign.The event is set for Sept. 29 at Austin's Auditorium Shores.Nelson is scheduled to perform alongside Joe Ely, Carrie Rodriguez, Tameca Jones and Nelson's sons, Lukas and Micah Nelson.If you're interested in seeing the show,O'Rourke is hoping to unseat incumbent Republican Sen. Ted Cruz in November's election.