The Twilight co-stars split in the summer after the actress confessed to an affair with her married Snow White And The Huntsman director Rupert Sanders, but their relationship seemed to be back on track as they promoted Breaking Dawn - Part 2, the final film in the vampire saga.
However, The Sun has now reported that R-Patz - who attended the Golden Globes without Kristen at the weekend - has called time on their romance, telling the star he just wants to be "good friends".
A source said: "She flew to LA and was supposed to be Rob's date for the Golden Globes, but he told her he wants to cool it off. He loves her but would rather go back to being good friends so they can rebuild their trust and focus on work after Twilight.
"Kristen's upset but understands."
However, the insider hinted that the 22-year-old On The Road actress is hoping for another chance with the British heartthrob, saying: "She's hoping he'll come round and time will be a great healer."