Actress Nayanthara reportedly is playing a secret agent in Vikram-starrer upcoming Tamil thriller "Iru Mugan", a source said."She will be seen as an undercover agent in the film. In this role, she will also get to do some action sequences," a source from the film's unit told IANS.This is the first time Nayanthara has paired up with Vikram, who will be seen in dual roles in the film.Currently being shot in Malaysia, the film is directed by Anand Shankar Also starring Nithya Menen as the second leading lady, "Iru Mugan" has music by Harris Jayaraj.