Hollywood starlet Kristen Stewart has apologised publically for cheating on her boyfriend with a married man.

Kristen has been dating her Twilight co-star Robert Pattinson for several years, though they have never openly confirmed their relationship.

However, photos have emerged of the actress, who has just starred in Snow White and the Huntsman, of her cavorting with the director of her new film.

41-year-old Rupert Sanders is married to model and actress Liberty Ross and has also released a statement apologising for his behaviour.

Kristen's announcement reads: "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 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."

Director Rupert followed suit and said: "I am utterly distraught about the pain I have caused my family.

"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."