SEOUL, South Korea — For years, anaylsts have said that one of the best kept secrets inside North Korea was that the despotic and often virulently anti-American leader at the time, Kim Jong-il, was a closet fan of Hollywood blockbusters, especially James Bond films. His son, the nation’s current leader, appeared to have picked up the bug, allowing the “Rocky” theme to be played at a special state concert.

Now, Hollywood may be testing the Kims’ improbable infatuation, as Columbia Pictures prepares to release a film — a comedy, no less — about a plot to assassinate the son, Kim Jong-un.

The North Koreans have reacted with their usual bluster, calling the movie an “act of war” and flinging threats at the Obama administration, which it implied had masterminded the film to undermine their nation.

“If the United States administration tacitly approves or supports the release of this film, we will take a decisive and merciless countermeasure,” a spokesman for its Ministry of Foreign Affairs said in a statement carried by the state-run Korean Central News Agency.