Sean Penn says Charlize Theron is the ''love of my life''.

The 'Gangster Squad' star is currently romancing the 39-year-old actress but was quick to correct a journalist who referred to the South African beauty as his ''girlfriend''.

He told French newspaper Le Parisien: ''No, no, excuse me, Charlize is not my girlfriend. She's the love of my life...

''We have a very strong relationship. [We] have known each other for a very long time. But we weren't together.''

Meanwhile, the 54-year-old actor previously admitted he would consider tying the knot with Charlize as his ''first marriage'', despite having been married twice already - to Madonna for four years and Robin Wright for 14 years.

He said: ''You say I've been married twice before but I've been married under circumstances where I was less informed than I am today, so I wouldn't even consider 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.''

Sean also admitted he was ''surprised'' that he was in love again.

He added: ''I'm surprised to be in love. Lots of reasons. 53 years old [when we got together] plus finally beginning to figure out why you haven't been happy in a single relationship? It could seem too late.

''To run into somebody now who you care about is a much passionate, deeper, truer and - God! - a much happier feeling. It's a lot more romantic and a lot more fulfilling to be in a relationship and to think you're a good person within it.''