A source told the gossip site that the 22-year-old star believes her 41-year-old director was in a "position of power over her" and she's "furious" that she's the one copping most of the heat.
The source adds that Kristen is terrified her actions may have irreparably damaged her career.
Just to rub it in, Hunger Games star Jennifer Lawrence has weighed in on the scandal … subtly, anyway.
The actress, who is known as Kristen's movie industry rival, commented to friends that she would never be unfaithful to her boyfriend, actor Nicholas Hoult.
"Recently, although she didn’t say Kristen’s name directly, she couldn’t resist having a subtle dig at her rival. She told a group of friends that she would never two-time Nicholas," a source told Radar Online.
"Jennifer then went on to say that she has received attention from many older men, especially powerful movie directors in the past, and would never want to jeopardise her career by getting involved with a married man.
"She was clearly referring to Kristen’s liaison with Rupert,” the source said.
According to another one of Radar's sources, Kristen is "insanely jealous" of Jennifer and was "thrilled' when she recently beat her Hollywood rival to the lead role in Lie Down in Darkness.