The Oscar-winning couple, which had been friends for years, struck up an unlikely romance in late 2013, and last summer (14), she signed on as Penn's leading lady in his new directorial project.

Theron reportedly called off the relationship in May (15), after 18 months of dating, but they found themselves back together on Wednesday (29Jul15) as they worked on reshoots - and they didn't seem happy about it.

Photos obtained by the show both stars looking stonefaced in between scenes in sunny Cape Town.

The Monster star previously admitted working together on The Last Face had put a strain on their romance.

She said, "There were moments where I was incredibly unfair to him. And moments where I felt like... he was incredibly unfair to me. But it makes you realise that no matter how complicated it gets, the priority is the relationship."

The Last Face features Theron as the director of an international aid organisation in Liberia who falls for a relief doctor, played by Javier Bardem.