Michael Weatherly, known for his role as Anthony DiNozzo Jr. on "NCIS," revealed that he didn't always get along with co-star Mark Harmon. Weatherly felt that they had contrasting personalities and approaches to work. After leaving "NCIS" to lead his own show, "Bull," Weatherly gained perspective and appreciation for Harmon's work on "NCIS." Fans have speculated about a possible return to "NCIS" for both actors, but it remains uncertain. Harmon left the show in 2021 but is still involved behind the scenes. Another Gibbs head slap between the two actors could be possible if they reunite.