Good news for NCIS fans! Mark Harmon will reprise his iconic Leroy Jethro Gibbs role in the flagship series. His return will be featured in a special (and first-ever) crossover event between NCIS: Origins Season 2 and the flagship series, which is well into its twenty-third season.The special crossover event will air on Veterans Day (November 11) on CBS and will feature a decades-spanning mystery connecting both the shows. It will also bring Mark Harmon back to his iconic role of Gibbs.Showrunners and executive producers David J. North and Gina Lucita Monreal announced Mark Harmon's cameo appearance in Season 23 as:“Four years ago, Gibbs disappeared to Alaska to live a life of solitude. We know how much fans have missed seeing Mark and have wondered what Gibbs is up to today. Well, on Nov. 11, we’re so excited to announce that Mark Harmon will return as Leroy Jethro Gibbs in the Origins hour of the NCIS crossover event. We don’t want to give too much away, but let’s just say Gibbs is no longer alone.”More on this in our story.Mark Harmon to make an iconic return in NCIS' cross-over event View this post on Instagram Instagram PostMark Harmon's Leroy Jethro Gibbs is one of the most beloved characters on television. The actor played Gibbs throughout the initial 18 seasons of the military procedural and made a quiet exit in Season 19. Gibbs revealed how he has decided to retire from the team and is ready to move on to the next chapter in his life. While fans were eagerly anticipating Mark Harmon's cameo in NCIS following his exit, he remained suspiciously absent (even from major events like the show's 1000th episode celebration).Following a long hiatus for Gibbs, Harmon finally returned to his iconic character in the Origins Pilot. Austin Stowell leads the spin-off series as a younger Gibbs.What is the cross-over event about? View this post on Instagram Instagram PostThe special crossover event between the flagship series and Origins will begin in the 1990s as a young Gibbs and his team take on the murder investigation of a small-town naval officer. The case will be unexpectedly reopened in the present day and will find its way to Alden Parker's team in the Navy Yard. Gibbs' strong connection to the case will pave the way for Mark Harmon's return in NCIS. For fans who were wondering about the Special Agent's life, the crossover episode will likely shed light on Gibbs' life in Alaska.The upcoming crossover is an impressive and creative way to connect the shows and bring Harmon for a brief cameo. Harmon revealed his excitement to return to his legendary role in NCIS (via Deadline):“I’m very proud of the storytelling that David and Gina are doing on Origins. They continue to push boundaries and dive deeper into the characters’ backstories. They came to me with an idea for Gibbs that I liked, and it seemed like a good time to check in with him. I hope fans enjoy it.”For storytelling purposes, NCIS: Origins Season 2 will air before the flagship series on November 11 on CBS. Stowell's younger Gibbs will kick-start the thrilling investigation at 8 p.m., which will be reopened decades later by Agent Parker's team in the flagship series at 9 p.m.Additionally, Mark Harmon also serves as one of the executive producers on both shows and the narrator for NCIS: Origins.Tune into the two-hour special crossover event to catch Mark Harmon in action as Leroy Jethro Gibbs with his OG team members.For the latest scoops on your favorite TV shows and movies, follow SoapCentral.