The NCIS universe is about to hit a monumental TV milestone, and CBS is honoring its legacy in a way that viewers need to know about.

As the decades-long franchise (which currently includes NCIS, NCIS: Hawai'i and NCIS: Sydney) prepares to air its 1000th overall episode, the network is taking fans on a journey down memory lane. As announced on March 26 in an official press release, CBS is airing NCISVerse: The First 1,000, a one-hour Entertainment Tonight special. The primetime event will premiere in place of a new NCIS episode tonight, Monday, April 8 at 9 p.m. ET. The 1000th episode milestone airs one week later, on Monday, April 15 at 9 p.m. ET.

While fans may be disappointed to find out that there is not a new episode of NCIS on tonight in the traditional sense, the brand-new special is a can't-miss event. In addition to providing viewers a first look at the making of the franchise's upcoming 1000th episode, it will also include exclusive interviews with the stars of NCIS shows past and present (including NCIS: Los Angeles, which aired from 2009-2023 and NCIS: New Orleans, which aired from 2014-2021), detailing behind-the-scenes moments and some of the cast and guest stars' favorite memories from working on the shows. What's more, ET's Kevin Frazier will host from the studio lot where NCIS is filmed.

ncis cast 2024 1000th episode special news
Sonja Flemming//CBS

While we don't know which cast members will make an appearance during the NCISVerse: The First 1,000 special, we do know whomever shows up will bring a boatload of nostalgia with them. And with the franchise's longevity on primetime television, CBS notes the special also touches on how the global phenomenon "changed the face of the real NCIS."

As far as what to expect from the actual 1000th episode of the NCIS franchise, CBS released key details on the plot line on March 28. Aptly titled "A Thousand Yards," Vanessa Lachey (from NCIS: Hawai'i) and Daniela Ruah (from NCIS: Los Angeles) guest star as the NCIS gets attacked by an enemy who comes with a mysterious past. Elsewhere, NCIS Director Leon Vance (Rocky Carroll) shares with his son why he continues to be part of the team, despite all the dangers that come with the position.

We'll be tuning in for what's sure to be a memorable ride!