Cannes 2015
Sean Penn and Charlize Theron Getty Images

Sean Penn and Charlize Theron have reportedly split after nearly a year and a half together.

According to a US Weekly report, the Mad Max Fury Road star has initiated the split from her Oscar winner fiancé, with whom she shares a deep friendship spanning decades.

In 2014 the couple got secretly engaged during a trip to Paris, the report claims, adding that there was no elaborate proposal as such. "There's no ring, but they are committed," an inside source told the magazine.

Penn, 54, was previously married to Madonna (1985 to 1989) and Robin Wright (1996 to 2010) but was eager to marry his latest love.

"You say I've been married twice before, but I've been married under circumstances where I was less informed than I am today," Penn told the magazine while speculating about his future with Theron.

"So I wouldn't even consider it a third marriage, I'd consider it a first marriage on its own terms if I got married again. I mean, I like the tradition. A friend of mine wrote a line, 'Without tradition, new things die.' And I don't want new things to die."

The 39-year-old South African actress remains unmarried and had a long-time relationship with Stuart Townsend. They separated in 2010.

"I was happy when I met Sean and I think that's why he fell in love with me - because I was happy and fulfilled and had a healthy dose of love for myself - and he's the same," the actress told Daily Mail in an interview . "He doesn't fill a hole in me and I don't fill a hole in him."