On Monday, CBS' long-running drama NCIS hit a major milestone with the release of its 450th episode. As the cast celebrated the achievement, actor Wilmer Valderrama paid tribute to Mark Harmon for his work on the show as Leroy Jethro Gibbs.
After NCIS premiered in 2003, the procedural drama reached a rare milestone in TV history with the premiere of its 450th episode.
While this was a huge achievement for the cast and crew, it was business as usual for the beloved agents. The episode Usual Suspects focused on family and saw the return of Alden Parker's (played by Gary Cole) father. Ahead of its release, NCIS' main cast members opened up about the show being on air for 20 years.