NCIS

NCIS' season finale is going to be pretty tough on Gibbs. Fortunately, he'll have an old friend to help him through it all.

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Muse Watson will reprise his role as Gibbs' mentor and best friend Mike Franks in the Season 10 finale, TVGuide.com has learned.  Of course, Mike was killed by the Port-to-Port Killer in Season 8, but his specter made an appearance in Season 9 during Gibbs' own near-death experience in the show's 200th episode.

The finale finds Gibbs (Mark Harmon) & Co. in the middle of a federal witch hunt related to the team's unconventional methods in the international pursuit of the man who killed Ziva's (Cote de Pablo) father and Director Vance's (Rocky Carroll) wife. The investigation will ultimately threaten some of the agents' futures with NCIS.

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"Gibbs is going to face some very tough decisions," executive producer Gary Glasberg tells TVGuide.com. "And who better to help him than his best friend, Mike Franks.  ... Imagine having a conscience, a moral compass, that speaks to you in the form of the wonderful Muse Watson. ... This is going to be a lot of fun."

Watson first revealed the news via his Facebook page.

NCIS' Season 10 finale airs Tuesday, May 14 at 8/7c on CBS.

(Full disclosure: TVGuide.com is owned by a joint venture between Lionsgate and CBS.)