Ashton Kutcher and Natalie Portman are just BFFs at first, until they start a sexual relationship with No Strings Attached.

The two hope to keep both their friendship and the sex going without any commitment, however jealousy and drama come into play. Originally, the movie was called Friends With Benefits ... which would've worked, too.

Wonder if Ashton's wifey, Demi Moore approved of the highly-sexual script? We'll admit, Ashton and Natalie look awfully comfortable together in bed.

Hot couple alert ... at least on-screen!