Stewart & Pattinson

Kristen Stewart is issuing a public apology for hurting her boyfriend of three years, Robert Pattinson, by having a fling with her Snow White and the Huntsman director, Rupert Sanders.

"I'm deeply sorry for the hurt and embarrassment I've caused to those close to me and everyone this has affected. This momentary indiscretion has jeopardized 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," Stewart said in a statement Wednesday.

Stewart & Sanders on May 29

Similarly, Stewart's fling, director Rupert Sanders, also apologised to his family in a statement for cheating with Kristen Stewart.

"I am utterly distraught about the pain I have caused my family," Sanders tells WHO Magazine in an exclusive statement. "My beautiful wife and heavenly children are all I have in this world. I love them with all my heart. I am praying that we can get through this together."

The British actor, 41, is married to actress-model Liberty Ross, with whom he has two young children.

News of Stewart's infidelity with the 41-year-old, married director comes about four years after the couple met while filming the first installment of Twilight, the vampire smash that thrust them into the spotlight before the film even arrived in theaters. Buzz that they were a real-life couple took off almost immediately.

Kristen Stewart's Affair With A Married Man

As Pattinson, 26, and Stewart, 22, have become increasingly open about their relationship, they've been photographed kissing and keeping cosy on date nights in Los Angeles.

Barely two weeks ago, the couple were all laughs at Comic-Con as they joked about their on-camera smooching scenes.