Inside Mark Harmon’s Drama With ‘NCIS’ Costar Michael Weatherly: ‘Nothing But Trouble’

NCIS fans are thrilled that Paramount+ is spinning off Michael Weatherly and Cote de Pablo’s characters Tony and Ziva for the 10-episode NCIS: Europe. The story will follow the pair, reunited after her supposed death, on the run across the continent.

Michael’s former costar Mark Harmon, on the other hand, is less enthusiastic. The two butted heads while on the original NCIS, with Mark, 72, miffed that Michael didn’t take the job seriously. “I was like a little kid who had one too many bowls of Count Chocula,” the 55-year-old later said.

For Mark, nothing’s changed. “As far as he’s concerned, Michael is a toxic pain in the butt,” a source tells Closer. “He’s nothing but trouble.” Indeed, in 2018, CBS was forced to pay his Bull costar Eliza Dushku $9.5 million after she accused him of sexual harassment. While Mark had his own brush with #MeToo, says the source, “he considers Michael a loose cannon.”