By Jon Boon - Breaking Celebrity News Reporter

Kristen Stewart is writing an apology letter asking for forgiveness from the wife of the director she cheated on Robert Pattinson with, Breaking Celebrity News is exclusively reporting.

The 22-year-old star of The Twilight Saga plans to say how sorry she is in a private note to Rupert Sanders’ wife Liberty Ross, after omitting the British model from the public apology she released Wednesday.

“Kristen didn’t feel it was appropriate to issue a public apology to Liberty once the story of her affair with Rupert broke,” a source close to the situation said.

“Instead, she’s going to do the decent thing and write Liberty a private letter expressing her deepest regret for her actions.

“She was thinking of including Liberty, Rupert and the kids in her public apology – but Kristen was so desperate to save her relationship with Rob she decided to concentrate on that first.

“Kristen feels she made a terribly naïve mistake and will do anything to make amends. The fact that Liberty and Rupert have two kids has now dawned on her and she feels awful for what she did,” the source revealed.

As Breaking Celebrity News previously reported, after getting caught red handed in a compromising situation with the married director, Kristen issued a public apology to her boyfriend, Robert Pattinson, on Wednesday where she called the illici