The 18th season of ’s flagship series finally returned this week for its first episode set during the . Although some fans knew what to expect after tuning in to spin-off series NCIS: New Orleans, others were shocked when Dr. Jimmy Palmer (played by Brian Dietzen) returned with crushing news.

NCIS just killed off a major supporting character off-screen after fast-forwarding to the middle of the coronavirus pandemic in this week’s episode.

Tonight’s instalment, The First Day, reunited Leroy Gibbs (Mark Harmon) and the team after a two week break, skipping the timeline ahead a few months.

While the show’s New Orleans-based spin-off has already tackled the devastating effects of the ongoing global health crisis, this was the first time the mainline series has dealt with the sad reality of the pandemic.

Fan reactions ranged from upset to downright appalled when Chief Medical Examiner Jimmy Palmer confirmed his wife, Breena (Michelle Pierce) had died after contracting COVID-19.

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As the episode went out on CBS, the audience immediately took to social media to discuss the show’s controversial decision.

On Twitter, one fan said: “Man this is such a tearjerker episode.

“Jimmy coping with the death of his wife Breena, now Sloane thinking about leaving and Gibbs left a little speechless.”

NCIS enthusiasts were also saddened by last year’s news that season 18 will likely be the last we see of Jackie Sloane (Maria Bello).

Viewers are now preparing themselves to say goodbye to yet another main cast member, and the news that an old favourite had been killed off-screen certainly didn’t help the transition.

Several fans joined the discussion to admit they thought they may have missed an episode when Jimmy confirmed the news in a significant, albeit brief, line of dialogue.

One surprised fan wrote: “I think I just suffered whiplash from that pronouncement from Jimmy. I feel like I’ve gotten lost somehow.”

While another added: “Was there an episode about Breena dying? Did I miss it? Or is this the first it's been mentioned?