Kristen Stewart has admitted she cheated on her boyfriend Robert Pattinson with her Snow White and the Huntsman director.
Reports surfaced yesterday about the affair and were confirmed overnight.
"I'm deeply sorry for the hurt and embarrassment I've caused to those close to me and everyone this has affected," Stewart said in a statement to People magazine.
"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."
The 22-year-old actress was photographed kissing Rupert Sanders on July 17 in LA.
Sanders, 41, is married to actress Liberty Ross and the couple have two children together.
He released an apology yesterday.
"I am utterly distraught about the pain I have caused my family," Sanders said in a statement to Access Hollywood.
"My beautiful wife and heavenly children are all I have in this world. I love them with all my heart. I am praying we can get through this together."
Cheating with her director. The Us Weekly cover that rocked Kristen and R-Patz