This is the last one, folks! After a bunch of delays and a short hiatus, the corona-crisis also hit the popular CBS show and season 17 of NCIS had to be officially cut short after production was halted. Episode 20 ("The Arizona") will therefore mark the season finale, but we've got a lot to look forward to at least.

NCIS Season 17 Episode 19 Recap: "Jimmy" And "Kasie" Save The Day!!!

The first teaser trailer for the final episode of season 17 promises some excitement as we get a glimpse at a very famous guest star, who will become the focus of an investigation led by "Gibbs" (Mark Harmon).

'NCIS' Season 17 finale: Can "Gibbs" prove that "Smith" is telling the truth?

NCIS Season 17 Episode 20: Is Christopher Lloyd lying?

Christopher Lloyd, known by many as "Doc Brown" from the Back to the Future movies, will play 95-year-old Navy veteran "Joe Smith" who claims to have served on the "U.S.S. Arizona" when it was attacked in 1941 at Pearl Harbor. "Smith" is determined to have his ashes laid to rest with his fellow sailors once he passes away.

The official description of Lloyd's character paints him as a "sharp, spry, and an unapologetic curmudgeon" who is being investigated by "Gibbs" and his team - will they confirm his identity or is "Smith" a fraud and has a totally different hidden agenda?!

NCIS' season 17 episode 20 airs on Tuesday April 14 at 8pm (7 central) on CBS!