Vanessa Lachey and Wilmer Valderrama Tease Action-Packed 'NCIS' and 'NCIS: Hawaii' Crossover (Exclusive)

The special episode airs Monday.

It's an NCIS-NCIS: Hawaii crossover!

NCIS stars Wilmer Valderrama and Katrina Law say aloha on Monday's episode of NCIS: Hawaii, when they drop by the CBS spinoff to revisit an old case once they learn that a key witness has turned up there with crucial evidence in the second half of the two-hour NCIS crossover event.

In ET's exclusive first look from the upcoming crossover, Valderrama and NCIS: Hawaii's leading lady, Vanessa Lachey -- who have been friends for two decades -- open up about reteaming for the special episode. "We have this amazing opportunity. We're going to do a crossover with the mothership," Lachey said in the video.

"What was really exciting was to have both of our shows and our families kind of meet and somehow connect our universes together," Valderrama said. 

"Tennant is reluctantly welcoming Torres, so that dynamic is going to be fun to see," Lachey teased, prompting Valderrama to have a chuckle and add: "Let's just say that these two have got to work together at some point."

Their co-stars also expressed their enthusiasm over bringing in some new flood to Hawaii.

"When we first found out that we were going to do a crossover episode with the OG NCIS was awesome," said Hawaii's Yasmine Al-Bustami, who plays Lucy. Added Law: "Getting to see different characters go over and interact and see how they interact and what shenanigans and plotlines come out of that is so much fun."

"I think what's nice about these particular episodes is they run back-to-back and it seems to me, like they could be more like a feature," said Hawaii's Alex Tarrant, who portrays Kai. Actor Noah Mills said that the crossover episodes are "awesome and action-packed."

The two-hour crossover event begins Monday on NCIS at 9 p.m. ET/PT, before culminating on NCIS: Hawaiat 10 p.m. ET/PT on CBS. 

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