Dustin Hoffman thinks about sex more than the average man.

The 'Quartet' director - who has been happily married to his wife Lisa since 1980 - admitted reaching the age of 75 hasn't stopped him from thinking about sex.

He told Germany's Bild newspaper: ''It's said, men would think about sex every seven seconds. I wish it was just every seven seconds.''

While Dustin and Lisa have sustained a 32-year marriage, Dustin admitted marriage isn't always easy, calling it an ''unnatural thing''.

He said: ''The better the relationship the shorter the time seems to be. We have arguments, we have conflicts of opinion, sometimes we are like 'now it's over'. I think marriage is a very unnatural thing. It is impossible, especially this concept of 'two become one'. As a pair you should never become one! The human you are now becomes a completely different human in ten years. You need a lot of luck for a long marriage.''

Dustin also revealed he thinks about death more than he ever did.

He explained: ''There's a point where death becomes relevant for your life. It a fellow, someone who's coming along with you all day. Before this point you think you could live forever.''