Entertainment Weekly reports that the actress will appear in the fifth episode as Michelle, the ex-wife of Winston (Chi McBride).
She will grudgingly team up with her former husband when he needs her help on a case. The character could also recur later in the season.
Thoms previously played Kat Miller on Cold Case and also starred in 2007 film The Devil Wears Prada.
Her Human Target debut, due to air in November, will also feature former Desperate Housewives actor Roger Bart.
Human Target will return to Fox on October 1.