Grant Heslov admits 'Argo' was a ''tricky'' film to market.

The producer says he wasn't sure how bosses could promote the film - which stars Ben Affleck and tells the story of the 1980 joint CIA-Canadian secret operation to extract six fugitive American diplomatic personnel out of revolutionary Iran - because it doesn't fall into one category and has a strange-sounding title.

He said: ''It's got an odd title, and it's a very hard film to sell. On one hand, it's a real nail-biter thriller and on the other hand, there's a lot of comedic moments in it, but it's not a comedy. If you sell it as a comedy, people are going to be disappointed. So it was tricky, but the studio did a great job. We're really happy with what they did with it.''

Grant produced the film with George Clooney and says they had been wanting to make it for over five years.

He told ''We found it about five years ago, and we developed it, and it was one of a few films that we had that we felt were ready to go. But George (Clooney) and I just hadn't had time to get it made or figure out what we were going to do with it. When we were shooting The Ides of March, we heard that Ben (Affleck) was interested, so we got together with him, and that's how that ball started rolling.''