'NCIS: Hawai'i' 's Vanessa Lachey Sheds Proud Tears for Historic Role, Teases Chemistry with Wilmer Valderrama

Vanessa Lachey has immense gratitude for her role on NCIS: Hawai'i.

The franchise's first female lead teared up while sharing a bit about her time on the show — ahead of the first franchise-wise crossover event. In a conversation on The Talk Monday, the 42-year-old actress walked onto the stage with tears in her eyes.

"I wasn't gonna get emotional, but you said I made history and I never really thought about that," she said. "I love that I get to be the one to be the first female lead. So, a massive thank you to CBS studios and CBS networks."

Lachey also spoke fondly of her NCIS costar Wilmer Valderrama — and teased their chemistry in the upcoming three-hour special. In their first crossover, the plot foreshadowed a possible romantic connection between the agents.

Off screen, though, Lachey says she and the 42-year-old That '70s Show alum "ended up becoming like brother and sister throughout the decades." Looking back on how she and Valderrama met early in their careers, she added, "I'm so grateful for that because when you run into the same people, I'm so grateful that we were just friends and nothing ever transpired to mess up the friendship."

The reason there seems to be a spark? Valderrama and Lachey have brainstormed something deeper than what's in the script.

"I've known him for so long, but we wanted to give the storyline a little something, so him and I secretly came up with this backstory," she said, though Lachey is keeping her lips sealed on that backstory for now.

The NCIS universe crossover will feature stars from NCIS, NCIS: Los Angeles and NCIS: Hawai'i as they all pay respect to a retiring professor. When that professor ends up dead, though, the team isn't so sure that their former mentor died by suicide. What ensues is a dangerous, three-hour hunt that brings all of the agents together to unmask the truth — and the culprit will go to any lengths to stop them.

Of filming with the entire NCIS crew, Lachey added, "It was just like one big happy family."

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The Talk's NCIS crossover special airs Monday at 2 p.m. ET/ 1 p.m. PT on CBS and is available to stream on Paramount+. The three-hour NCIS crossover event kicks off Monday night at 8 p.m. ET (cable subscribers can watch the event live on CBS, and Paramount+ Premium subscribers will be able to live stream the event through their local CBS affiliate station).