Pictures have since emerged of the Twilight actress, 22, in the arms of the 41-year-old Snow White And The Huntsman filmmaker - who has two young children with model wife Liberty Ross.
According to People, Kristen said: 'I'm deeply sorry for the hurt and embarrassment I've caused to those close to me and everyone this has affected'
Clearly a reference to the fans and Sanders' wife.
But while she chose not to mention her by name, she used the statement to beg forgiveness from Pattinson, and state her love for the Twilight heartthrob.
She said: 'This momentary indiscretion has jeopardised the most important thing in my life, the person I love and respect the most, Rob. I love him, I love him, I'm so sorry.'
As yet there has been no public response from Robert who is privately said to be 'devastated and humiliated.'
But according to RadarOnline, Hollywood's highest paid actress is intending to write a private letter to the British catwalk star to attempt to make amends, as she didn't feel it was right to speak in public to her.
A source told the website: 'Kristen didn’t feel it was appropriate to issue a public apology to Liberty once the story of her affair with Rupert broke.
'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
Culled From Mailonline