(TMZ) -- Kim Kardashian is doing more than just tweeting about an upcoming prison execution -- we've learned she's now actively lobbying for death row inmate Rodney Reed ... and his family is extremely grateful.
Sources with direct knowledge tell TMZ ... Kim has recently been in touch with high-ranking Texas government officials to discuss Reed's scheduled killing on November 20 -- trying to get them to hold off on the execution and reopen his case. We're told Kim believes there are new witnesses and evidence to exonerate Reed, and implicate the real killer.
Reed' brother, Rodrick, posted a thank you note to Kim Monday, saying, "I want you to know you are a major God-send to my family - more than you may ever fully realize in this lifetime. You are a blessing to all the families you advocate for. We're so glad you have publicly voiced that you also believe he is innocent."
Kim also spoke with Rodney just last week from death row to let him know she was working to help his case.
We're told one of the things Kim has sent to officials is a letter from Reed's brother, who wrote her asking for help with the case. Our sources say Kim's also been working behind the scenes to provide legal resources to Reed as he tries to get a stay of execution.
Reed was convicted for the murder of Stacey Stites in Bastrop, TX -- where cops initially said he'd raped, assaulted and strangled her to death. He's maintained his innocence for over 20 years now, and just recently ... a former inmate claimed to know the real murderer.
A guy named Arthur Snow filed a statement with the court alleging Stites' own fiance -- who served time for a different crime -- confessed to him while behind bars that he killed her for sleeping around. Snow says they were both part of the Aryan Brotherhood in prison. Stites' fiance has denied this.
There are other folks who've come forward in recent weeks on Reed's behalf, and there's been a rallying cry to get the case reopened -- which Kim has joined with time running out.