Seven of Nine (born Annika Hansen) is a fictional character introduced in the American science fiction television series Star Trek: Voyager. Portrayed by Jeri Ryan, she is a former Borg drone who joins the crew of the Federation starship Voyager. Her full Borg designation was Seven of Nine, Tertiary Adjunct of Unimatrix Zero One. While her birth name became known to her crewmates, after joining the Voyager crew she chose to continue to be called Seven of Nine, though she allowed "Seven" to be used informally.