Robert Pattinson and Kristen Stewart are one of our favorite celebrity couples. We’ve loved watching them in love, on-screen and off, so much that this latest news on their relationship is devastating: Kristen allegedly cheated on Rob.

People reports that Kristen, 22, had a “brief fling” with Rupert Sanders, the married director of her recent film Snow White and the Huntsman. “Kristen is absolutely devastated,” a source tells the magazine. “It was a mistake and a complete lapse in judgement.”

“She wasn’t having an affair with Rupert. It was just a fleeting moment that shouldn’t have happened. She never meant to hurt anyone. She’s a good person who just made a bad choice,” the source says. The source alleges that the tryst occurred not when Kristen and Rupert were filming, but recently.

In a separate report, Us Weekly claims the encounter happened July 17 in Los Angeles. According to them, the two were caught by photographers in what is being referred to as a “marathon make out session.” One photographer told the magazine, “It seemed like they couldn’t get enough.”

Rupert, 41, who is married to British Vogue model Liberty Ross, 33, has two children, ages 7 and 5.

Filming on Snow White and the Huntsman began in August of 2011 and wrapped in December, with the film having been released this past May. We have to wonder if this is something that began months ago, when Kristen and Rupert were working together for those four months, or if it truly is a recent development, as People claims.

Rob and Kristen have been together for the past four years, since meeting each other on the set of the first Twilight film. The two even live together. While we don’t know Kristen’s stance on cheating, Rob has been very vocal about how he’s against cheating, even saying how he doesn’t understand it.

沪江娱乐快讯：据最新一期的《美国周刊》报道，罗伯特·帕丁森(Robert Pattinson，26岁)女友克里斯汀·斯图尔特(Kristen Stewart，22岁)和《白雪公主与猎人》(Snow White and the Huntsman)导演鲁伯特·山德斯(Rupert Sanders，41岁)亲密约会的照片被曝光。

据悉，山德斯为已婚人士，他的妻子是英国《Vogue》杂志模特丽波缇·罗斯(Liberty Ross)，二人共有2个小孩，分别为7岁和5岁。他和斯图尔特的马拉松地下恋情被摄影师描述为“似乎两人都是意犹未尽”。

“克里斯汀这下全毁了，这是个错误，是完全的判断失误”，有消息向《人物》杂志称。另一方面，也有对此持包容态度的消息，“她和鲁伯特没有关系。那只是极其短暂的瞬间，本不该发生。她不想伤害任何人。她是个好人，只是做了错误的选择。”

斯图尔特和帕丁森在不久前还一同亮相动漫展，二人还拿镜头前接吻的场景开玩笑的。

目前克里斯汀·斯图尔特和山德斯的发言人对此都没有表态。