Charlize Theron (L) and Sean Penn

Engaged Oscar winners Sean Penn and Charlize Theron have ended their romance after about 18 months.

Entertainment Tonight reported the split, but offered no reason for it. The outlet also did not say exactly when it occurred.

Theron recently spoke to Elle UK about her passionate relationship with Penn.

"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," she said. "There were moments where I was incredibly unfair to him. And moments where I felt like... he was incredibly unfair to me."

The film stars reportedly knew each other for several years before they began dating.

Penn, 54, was previously married to pop star Madonna from 1985 to 1989 and to House of Cards actress Robin Wright from 1996 to 2010.

Theron, 39, lived with her longtime beau, Irish actor Stuart Townsend, from 2001 to 2010.