Charlize Theron and Sean Penn have reunited in South Africa.

The former couple - who split six weeks ago after 18 months together - were forced to meet up in order to undertake reshoots on 'The Last Face', which the 39-year-old beauty has the lead role in and the 54-year-old star is directing.

The pair appeared stone-faced and were described as ''tense'' whenever they were in close contact with one another on the set.

Charlize - who has a three-year-old adopted son, Jackson - previously admitted working with her then-fiance on the movie had been tough.

Speaking before they split, she said: ''Putting aside that he's my partner, he's the love of my life; for the first time, I felt that my work was really bleeding into my life and that made it hard. 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 former couple were last seen together at the Cannes Film Festival in May and were believed to have called time on their relationship soon afterwards.