We are the last people in the world to own a DVR, so Mindy and I had time to kill during the ad breaks in last night’s kick-ass Lost. I don’t remember why, but we were trying to figure out what makes it okay to call some actors, but not others, by their last names only. (“Did you see that new De Niro movie?” vs. “Did you see that new Pitt movie?”)

Obviously it’s not just level of stardom, since Brad Pitt or Will Smith are as A-list as you get, and they don’t work. For a while we thought it was just for Italians (or Italian-sounding names, anyway) only:

But then a Shutter Island trailer came on and I tried saying, “I hear Ruffalo is really good in that,” which cracked us both up.

Turns out it’s easy to come up with counter-examples to the “Italian rule” though:

It seems that you need some perfect storm of (a) mellifluous last name, (b) distinctive last name, and (c) iconic stardom to get the last-name nod. I presume (a) is what gives you all the non-Cage Italians, and (b) is what disqualifies iconic stars like Harrison Ford and Cary Grant.

I guess I could have added that you also have to have (d) a penis, since a few minutes’ thought only reveals one actress in the whole history of movies with this kind of “last name recognition.” (Stars who needed a man to make the cut, a la “Bogie and Bacall” or “Tracy-Hepburn,” don’t count.) Who am I thinking of?

Edited to add: Readers actually found two such actresses, here.