"NCIS" season 13 is going big, seeing that its return on air from a three-week break marks the 300th episode of the long-running series. The episode, titled "Scope," will be big on both casting and storyline.

"Private Practice" alum Taye Diggs will be part of the ensemble for this episode. The actor will play the role of Special Ops member Marine Gunnery Sergeant Aaron Davis, who Gibbs will be interviewing for a case.

The "NCIS" season 13 episode tells the story of an American couple killed in Iraq. At the very same spot where the ambush happened, the same type of incident happened six months back with Diggs's character being the only survivor from the group of Special Ops there.

In order to prevent this from ever happening again, Gibbs reaches out to Davis to gain any information that will help them solve the case. From the looks of it, he may not be all too keen to help the agent.

In Walter Reed Medical Center, Davis undergoes a music therapy program to recover from the post-traumatic injuries he incurred during the attack. As he tries to move on from the incident that killed his pals, Gibbs comes to him in "NCIS" season13 episode 18 wanting him to remember every detail about what happened there.

"NCIS" executive producer Gary Glasberg said in a statement picked up by Entertainment Weekly that Diggs is perfect for the role. For the uninitiated, Diggs has appeared in tons of Broadway musicals such as "Rent."

"For our 300th episode, we needed a guest actor who could proudly portray one of our nation's wounded warriors as well as participate in a very touching musical performance," the "NCIS" EP said.

"This emotionally charged role is tailor-made for Taye Diggs, and we are so thrilled and honored to have him join us," Glasberg added.

Meanwhile, "NCIS" season 13 seems to be preparing Michael Weatherly's exit. In the March 22 episode of "NCIS", Robert Wagner will appear as Weatherly's character's dad Anthony DiNozzo Sr.

The synopsis for the said "NCIS" season 13 installment teases that Tony may meet his long-lost sister. This could ultimately set up his departure from the team.

"NCIS" season 13 resumes on March 15 on CBS with "Scope."