The NCIS: Hawaii countdown is on.

We're now just three weeks away from the premiere of the new series, which launches on Monday, Sept. 20. This week, star Vanessa Lachey also shared a new trailer for NCIS: Hawaii, and it shows action from the show for the first time!

NCIS: Hawaii: Watch official trailer ahead of release date

"Jane Tennant reporting for duty!" Lachey wrote on Twitter with the preview of her new NCIS team leader. The star called it an "exclusive" trailer, which only appears to have shown on television so far.

The preview gives a solid first impression of Lachey as Special Agent In Charge "Jane Tennant." In the clip, she comes off as a strong leader who is caring but still commands respect from her team.

Lachey wrote of the trailer: "Not gonna lie, I cried when I saw it, but happy tough kick ass tears!" She then reminded fans to tune in for the premiere on Sept. 20.

And premiere day will be a big one in the NCIS universe, as the main series will also kick off season 19 before NCIS: Hawaii premieres.

NCIS and NCIS: Hawaii 2021 premiere date: Sept. 20

NCIS is moving to Mondays for the first time in series history, and it will air before NCIS: Hawaii this season.

NCIS fans are tuning in to find out what happened to "Gibbs" following that dramatic explosion in the season 18 finale. Star Mark Harmon is also scaling back his work on the show while new actors have joined the cast.

Add on the whole new NCIS: Hawaii series and there's plenty to watch for on CBS Mondays. NCIS and NCIS: Hawaii premiere on Sept. 20, while NCIS: LA follows on Oct. 10.

You can also click here for more on Vanessa Lachey's starring role in the new series!