As previously announced, Curtis will play Charlotte Ryan, a career woman and single mom who works as a psychological operations agent in the Office of the Inspector General in the Defense Department. The Lord of the Rings star will portray her right-hand PsyOps agent, according to Entertainment Weekly.
"I've been a big fan of Sean's for years and this is a part we literally tailored for him," executive producer Gary Glasberg tells the magazine. "We couldn't be happier to have Sean join us.
Curtis and Astin's episode is slated to air in late March. NCIS airs Tuesdays at 8/7c on CBS.