Charlize Theron says Sean Penn is the love of her life.

Charlize Theron and Sean Penn

Charlize Theron and Sean Penn

The 39-year-old actress has been dating the 'Gunman' star - who was previously married to Madonna and 'House of Cards actress Robin Wright - since early 2014 and has confessed she thinks he is her soulmate.

Speaking about working with him on the upcoming movie 'The Last Face', 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."

The 'Mad Max: Fury Road' star admitted it was difficult having to put their relationship to one side in order to benefit the film but went on to suggest that she would choose Sean, 54, over her career.

The blonde beauty told Elle magazine: "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."

Meanwhile, Charlize - who has a three-year-old adopted son named Jackson - recently revealed she wants to have a child with her fiance, who has adult children Dylan and Hopper from his marriage to Robin.

Asked if she would like to have another child, she said previously: "Yes. I always wanted to have children."