Ashton Kutcher is desperate to keep his relationship with Mila Kunis under wraps, revealing he "learned the hard way" about valuing his privacy following his failed marriage to Demi Moore.

Ashton Kutcher learned to value his privacy "the hard way".

The 'Two and a Half Men' actor is desperate to keep his new romance with former 'That '70s Show' co-star Mila Kunis private following his high-profile marriage to, and split from, actress Demi Moore.

In an interview with ELLE magazine, the actor said: "You know, I've learned the hard way how valuable privacy is. And I've learned that there are a lot of things in your life that really benefit from being private. And relationships are one of them. And I am going to do everything in my power to have this relationship be private."

The 35-year-old star met Mila, 29, on the set of the hit sitcom - which ran from 1998 to 2006 - in which they played love interests, but their real-life relationship didn't blossom until last year following his split from the 'Charlie's Angels: Full Throttle' actress.

Quizzed about their transition from co-stars to couple, he responded: "People will fill in the blanks however they want."

Ashton, who joined 'Two and a Half Men' in 2011 following Charlie Sheen's departure from the show amidst a public feud with creator Chuck Lorre, added that people perceive him to be a demanding Hollywood star but he insists he's really "just a geek".

Speaking on his initial meeting with Chuck, he said: "There was an impression that I was this sort of larger-than-life, with-a-posse kind of guy. After we met and hung out, he realised I was just a geek."