Charlize Theron is actually pretty close to Liberty Ross, the wife of Rupert Sanders, who Kristen Stewart decided to make him her playtoy for six months. Now Charlize is joining the mad-at-Kristen bandwagon too. via the New York Post:

Theron struck up a friendship with Stewart on the set of [Snow White and the Huntsman], but is also friends with [director Rupert] Sander's wife Liberty Ross, who also had a part in the movie. The scandal involving Stewart and Sanders that broke this week now has put Theron in a "difficult position," the site says.

"Charlize is absolutely fuming with Kristen for having an affair with Rupert," an insider tells Radar. "She is very tight with Liberty, has often socialized with the family over dinner and cannot believe Kristin has done this ... When they were filming... Charlize felt like an older sister to Kristin, and they were always sharing advice."