Renee Felice Smith Renee Felice Smith

Nell (Renee Felice Smith) tackles her most challenging security assignment to date on Monday's episode of NCIS: Los Angelesgoing undercover as Hetty (Linda Hunt).

Eric Christian Olsen teases a "revealing" Densi moment and more NCIS: LA developments

With Hetty under investigation by the Department of Justice (and also apparently the target of a more sinister plot, if last week's episode is any indication), the team mobilizes to protect her. And for Nell, that means masquerading as her boss.

Remarkably, Smith says she only spent five minutes in the makeup chair for her disguise, since Hunt wears minimal makeup on the show. The real heavy lifting in terms of her costume came via her wig and mimicking Hunt's mannerisms.

Check out an exclusive gallery of Smith's transformation and get her behind-the-scenes take on the plot here.

NCIS: LA airs Mondays at 10/9c on CBS.

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