The cast of NCIS is currently filming and airing its twelfth season, which is a huge accomplishment for a TV series.

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On Tuesday, Australia's Studio 10 uploaded a behind-the-scenes look on set of the number one, most-watched drama in the world.

In the video below, Pauley Perrette, Michael Weatherly, Sean Murray and David McCallum all chat about the series and their characters.

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Weatherly serenaded the Australian reporter with a song on the fly since he does have a musical background aside from being a terrific actor.

"It is without question the longest relationship I've ever been in," Weatherly said of his gig on NCIS, portraying Tony DiNozzo.

Then, Perrette dished that she and her character Abby Sciuto are nothing alike.

"People that know me really well, don't think that I'm like Abby at all," she revealed, adding, "And people that don't know me, they're just like, 'Oh you're just like her.'"

She did share who Abby is modeled after in terms of her mannerisms.

"I patterned Abby's behavior-Everything that she does physically is after this rescue dog I had," she shared, adding, "So the way Abby stands...Is exactly like this dog."

Murray actually talked about living in Australia as a kid since his mother is Australian.

Then, McCallum shared, "It's quite amazing," how long NCIS has been running for and what's to come still.

On Thursday, Murray dished on Twitter that he has sustained injuries on set of the CBS drama.

He "slipped on wet concrete while running." That damaged tendons in his right hand and "never fully healed."

NCIS airs on Tuesdays at 8 p.m. ET on CBS.