"NCIS: Red" will be launched in the spring with an episode of "NCIS: LA" serving as the pilot.
Alexy's character, Special Agent Claire, is described as "educated, worldly, athletic and as tough as she is beautiful," a synopsis of the show read.
Scott Grimes, John Corbett and Edwin Hodge will also be in the cast, and Miguel Ferrer will reprise his role as NCIS assistant director Owen Granger from "NCIS: LA" on the spinoff, The Hollywood Reporter said.
Alexy previously appeared on DirecTV's "Damages."
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