BAD blood between “NCIS” star Mark Harmon and the show’s creator/producer Donald Bellisario, has led to trouble on the set of TV’s highest-rated military series.

Bellisario, who also created “Jag,” said over the weekend that he is leaving the show to work on a new series for CBS.

Rumors of tension between the two men have been flying for several months.

TVGuide.com reported that Harmon was upset with Bellisario’s “chaotic management style” that required long days of shooting because of last-minute changes.