Kim Kardashian and Rihanna are among the celebrities campaigning to prevent the execution of a prisoner convicted of killing a woman in 1996.
Rodney Reed has been on death row since he was found guilty in 1998 of murdering Stacey Stites when he was 28.
Now 51, Reed is scheduled to be executed on 20 November.
The 20-year-old's body was found on a rural road in Bastrop County, outside of Austin, Texas, according to US news reports.
Prosecutors argued Reed "strangled and killed" her "during an aggravated sexual assault".
Reed was identified by DNA evidence taken from the crime scene, according to the Texas government website. However, campaigners claim the DNA resulted from a consensual sexual relationship with the victim.
The death row prisoner has maintained his innocence - and his lawyers claim there is new evidence which would free him.
This includes a sworn statement by a fellow prisoner that Stites' fiance, a former police officer called Jimmy Fennell, had allegedly confessed to the murder while serving time for abducting and raping another woman.
The inmate says Fennell, who is white, was angry about his fiance was having an affair with a black man.
Fennell, who has been released, was an person of interest in the murder, it has been reported.
Other witnesses have also said that Fennell was angry over the alleged tryst and had threatened to kill her prior to the murder, according to the Innocence Project.
Fennell's lawyer, Robert Phillips, could not immediately be reached for comment on Tuesday. In a statement to CBS News on Monday, the lawyer said Fennell was not involved in Stites' killing and had been devastated by her death.
More than one million people have signed a petition urging Texas Governor Greg Abbott to stop the execution - with celebrities joining the cause.
Singer Rihanna wrote: "One Click!! SIGN the petition if you don't believe the Government should kill an innocent man!!!"
Model, reality star and entrepreneur Kim Kardashian-West, who has campaigned on behalf of other prisoners and is studying law, added her voice.
She wrote: "PLEASE @GovAbbott How can you execute a man when since his trial, substantial evidence that would exonerate Rodney Reed has come forward and even implicates the other person of interest."
She added in capital letters: "I URGE YOU TO DO THE RIGHT THING."
Andrew F MacRae, an attorney for Reed, told NBC News that Reed's advocates appreciated the support, "celebrity and otherwise."
"Although I hear consistently that our country is becoming more divided, there is at least one thing on which all Americans seem to be unified - the importance of justice," he said.
On 30 October, Reed's legal team filed for an application for clemency.
The governor's office did not immediately return a request for comment when asked by US media.