Vanessa Lachey, who is married to 98 Degrees singer Nick Lachey, plays Special Agent in Charge Jane Tennant on "NCIS: Hawaii," making history as the first woman to helm a series in the long-running franchise, which includes the original "NCIS" that's now in its 19th season as well s three previous spin-offs.

As Tennant's second-in-command on "NCIS: Hawaii," Noah Mills obviously has a lot of interaction with Lachey, whom he calls an "amazing" co-star.

"Vanessa is so generous," Mills shared in the interview. "She really is. The way she makes the crew feel, the way she organizes and the energy she brings is really astonishing ... Vanessa is a leader, and her generosity and rallying of the troops in real life, it works so well for the show and for [her character] Jane."

Mills said that comradery behind the scenes spills over onto the show itself, too. "That's all stuff that's symbiotically happening with us in real life," he said. "It's bleeding into the show and mixing together. Season 1 was a really nice mix of that, and Vanessa was an amazing lead and amazing leader and kept us all together. She fell in love with the island and the crew and everybody, and we all followed suit. She's awesome."

But beyond being a strong leader on the set, Lachey is also someone who keeps the cast and crew laughing and on their toes. "Vanessa's a goof ... she's so funny," revealed Mills. "We're a goofy, goofy set, [but] we work hard and we get it done. Maybe some of that stuff is too ... not peachy enough, but, yeah, we have a lot of fun."

"NCIS: Hawaii" airs Mondays at 10:00 p.m. ET on CBS.