NCIS premiered in 2003 on CBS and to date it has aired fourteen full seasons, making it the second longest-running non-animated U.S. primetime TV series currently airing. The show has won numerous awards, including a People's Choice Award for their lead actor, Mark Harmon ("Leroy Jethro Gibbs").

The pretty actress with Chilean roots, Cote de Pablo, started her career when she was a child. After studying music and theater, she was only able to get smaller roles in low-budget stage productions. Her big break came with the role of "Ziva" in NCIS. This photo was taken back in 2004...

Actor Michael Weatherly really looked different back in 2002. Did you know that he was engaged to Hollywood beauty Jessica Alba once? They had met during the filming of Dark Angel. However, since 2009 Weatherly has been married to the doctor Bojana Jankovic.

From the very beginning of the show, in 2003, until 2016 Weatherly had the role of the good-looking special agent "Anthony DiNozzo". "Tony" has Italian roots and is a real womanizer.

Recognize him? This photo of Mark Harmon also known as "Gibbs" was taken in 1988 during the filming of "Stealing Home", in which Mark Harmon starred with Meryl Streep. Harmon first appeared on a television show in 1975.

Mark Harmon is one of the true NCIS veterans and has been with the cast from the start in 2003. Supervisory Special Agent "Jethro Gibbs" is the leader of the "Major Case Response Team" and is considered one of the best snipers in the world. In real life, Mark Harmon is married to actress Pam Dawber since 1987.They have two sons together.

Wow, in 2010 the actor still looked really young! Sean Murray got his career started in 1993 with the film This Boy's Life, in which he was featured alongside Leonardo DiCaprio.

Since 2003, Murray has had the role of special agent "Timothy 'Tim' McGee". His character's talents include a technical specialist and an excellent hacker but sometimes a little slow on the draw...

Even in real life the actress wears her hair very dark and also her clothing style strongly resembles the one of her NCIS character "Abby". But these are not the only things Pauley has in common with "Abby"! Perrette has studied Sociology and Psychology and completed her master's degree in Criminology. The actress is also very strong advocate for gay rights.

Ever since the show premiered in 2003, Pauley played "Abby Sciuto", who is a forensics expert and an IT-specialist. "Abby" was regarded particularly eccentric and her methods tend to be rather unconventional. Her trademark was the gloomy Gothic style.. Unfortunately, Pauley left the show at the end of season 15!

Always worth a second look! This photo of actress Lauren Holly, known as "Jenny Shepard" in NCIS, was taken almost 15 years ago.

Between 2003 and 2008, Holly was featured in the role of the former "Director of the Naval Criminal Investigative Service", "Jenny Shepard". Due to her previous affair with "Gibbs", it was not always easy for them to work together. Unfortunately, "Jenny" dies at the end of the fifth season when she succumbs to the injuries of a gunfight.

Do you recognize him? Yes, it really is "Ducky"! This photo was taken on the set of the 1966 film The Spy with my Face. McCallum was born in 1933 and has been working in show business since 1957.

As the forensic pathologist "Doctor Donald 'Ducky' Mallard", David McCallum usually tells the quirky story of his long and winding career to almost anybody. Also, he usually talks to the bodies he is supposed to examine.

This picture of the handsome Rocky Carroll was taken more than 10 years ago. Striking: The actor has hardly changed. In addition to NCIS, Carroll has also appeared in shows like Grey's Anatomy, E.R. and Law & Order.

In NCIS, Rocky Carroll plays the character of "Leon James Vanc", who becomes the "Director of the Naval Criminal Investigative Service" after the death of "Jenny Shepard" in 2007.

This is what the beautiful actress Sarah Alexander looked like in the year 2003. In the early days of her career, she starred in critically acclaimed independent films. Her big breakthrough came with her role of "Caitlin 'Kate' Todd" in NCIS.

From 2003 to 2005, Sasha Alexander starred as special agent "Caitlin Todd". Before and after NCIS, Alexander was featured in numerous series such as Dark Blue, Dr. House and The Nine. From 2010 until 2016 Sasha Alexander also appeared as "Doctor Maura Isles" in Rizzoli & Isles.