NCIS star Wilmer Valderrama has fans 'worried' as he teases big season 22 episode

NCIS star Wilmer Valderrama has shared a behind-the-scenes look at a big episode from the upcoming 22nd season and while fans couldn't be more excited to see the new instalment, some were left a little worried.

The actor, who plays Special Agent Nick Torres in the CBS show, posted a video filmed from the set of the show, which returns to screens in October.

"Hey ladies and gentlemen. I'm on the set of NCIS with my partners in crime here ," said the actor, panning the camera to his co-stars Diona Reasonover, Sean Murray and Gary Cole. "We can't tell you what's happening now but this is not a small episode. That's all I can say," he added, holding up his hand, which was in handcuffs.

In the caption, Wilmer penned: "In scene…. October 14... Shhhh."

Fans were quick to react to the post, with many delighted with Wilmer's latest update. One person penned: " Totally can't wait for season 22 so excited, wow the episode looks so good," while another added: "Cannot wait for the new season!"

© Sonja Flemming/CBS

However, some fans were left a little worried as they noticed Katrina Law, who plays Agent Jessica Knight, was nowhere to be seen. " Ok now I'm worried . I hope Katrina does come back!!" one fan wrote, while another added: "I don't see Katrina???"

Fans have been patiently waiting to find out Agent Knight's future with NCIS after she accepted a new job as the chief REACT training officer at Camp Pendleton at the end of season 21.

© Robert Voets/CBS

Katrina has been fairly active on social media in recent weeks, sharing photos from her family trip to Disneyland as well as showing off her new blonde hairdo .

Since Katrina hasn't posted any snaps from the show's set, fans have been wondering if she has left the show for good. In the comments section of one of her posts, one person penned: "Apparently NCIS Season 22 is already in production - I take it you're not part of it due to your present hair color and location?" while another viewer added: "I'm going to go out on a ledge and guess you're not coming back to NCIS? "

© CBS

Addressing her storyline in a recent interview with TVLine , Katrina said: "I think that at the end, Jessica has to take this position because she knows deep down this is what she wants . She wants a career, she's very ambitious, and to her a long-distance relationship isn't the end of things."

© Robert Voets/CBS

The actress continued: "At the same time, maybe it is, if it doesn't work out. She has to go forward and see where these things lead, she can't settle into something she knows will ultimately make her angry and have regrets."

When asked if fans can expect her return in season 22, Katrina said: "Hmmm…. Better tune in for that season opener!"