In real life, filmmaker Renny Harlin doesn't have an apartment in New York City. But that hasn't prevented the fictional Larry David from housesitting for him in Manhattan during the current season of "Curb Your Enthusiasm."

Harlin only discovered his quasi-cameo role on the HBO comedy series when he was told about it by reporters at the premiere of his new film, "5 Days of War," on Tuesday night.

"Everyone...