The 40-year-old South African actress and 55-year-old American director attended a photocall for The Last Face at the 2016 Cannes Film Festival, where the movie is competing for the Palme D'or.
Javier Bardem, Jean Reno, Adele Exarchopoulos and Zubin Cooper also attended the event, allowing ex-partners Theron and Penn to keep their distance. The photocall came nearly a year after the pair's split.
Theron turned heads in a lace Givenchy dress, while Penn kept it casual in a t-shirt, pants and jacket. The actress and Bardem play aid workers and love interests in the film, with Penn as director.
Theron and Penn dated over a year before breaking up last summer. The actress discussed both the relationship and The Last Face in the May issue of British GQ, calling the collaboration "a beautiful film."
"We both care enough about each other to know we care about this movie together," the star asserted. "Do I wish people would respect that and look at the film for what it is? Of course I do, but I know I'm not God and that's probably not going to happen."
"I saw him yesterday. He's still editing. But people want to create chaos with celebrities, as if [when] there's not drama around it, somehow it doesn't sell," she added, again denying she ghosted, or abruptly ceased all contact with Penn.
The Last Face, which has yet to set a theatrical release date, premiered to largely negative reviews at the festival. Penn defended the movie after the screening, saying, "I stand by the film as it is, and everyone is going to be entitled to their response."