Vanessa Lachey is counting down to the big three-show “NCIS” crossover.

The “NCIS: Hawaii” star changed locales from the tropical island to Los Angeles to take part in the grand-scale crossover event between the three “NCIS” shows — “NCIS”, her “Hawaii” offshoot and “NCIS: LA”. Only ET was with Lachey on the set of “NCIS” on Wednesday as she went to work on the anticipated crossover.

“Today is the first day that all three ‘NCIS’ shows are meshing in the first episode,” the actress teased. “It’s going be ‘NCIS’ and ‘NCIS: Hawaii’, then ‘NCIS: LA’… It’s really great because we were all in one room and everyone’s asking, ‘Does my character know your character? When have you guys met? When did you guys meet?’ So we’re all figuring it out for ourselves.”

Lachey said she’s excited for viewers of the “NCIS” franchise “to start coming up with their own theories as well, as to our backstories.”

While she primarily spends her time in Hawaii leading the charge alongside her castmates, she revelled in the new energy that all the different characters bring when they’re in the same room together.

“It’s always funny to me to see how we’re all so serious in procedural television but we’re all just normal moms and dads and people. So I just love being able to like kick it with them and talk about life and just hang out and eat snacks,” she shared. “I mean, we do work, don’t get me wrong. I act like we’re just sitting around all day but it’s just been really fun to see the other side of everyone else.”

Lachey’s husband, Nick, stayed back in Hawaii where he served as ET’s guest co-host on Wednesday’s show with ET’s Kevin Frazier and Nischelle Turner at the Sheraton Waikiki. The “Love Is Blind” co-host offered his opinions on the current relationship statuses of the season 3 couples and responded to Lauren Speed’s accusation that the show cuts out Black women.

MORE FROM ET:

‘NCIS: Hawaii’s Alex Tarrant and Tori Anderson Go Paddle Boarding With ET (Exclusive)

Vanessa Lachey on Secret to Her Marriage With Nick and ‘NCIS: Hawaii’

‘NCIS’: Mark Harmon Removed From Season 20 Opening Credits

‘NCIS: Hawaii’s’ Noah Mills Interviews Cast Ahead of ‘NCIS’ Crossover