Eden Riegel is heading to primetime.

The long-time soap opera star (All My Children, The Young and the Restless) will appear on the fourth episode of Castle's new season in October.

As first reported by TV Guide, the Daytime Emmy Award-winner will portray Rachel Goldstein, the sister of a man killed by an antique pistol. Beckett and Castle will investigate the crime.

In other recent Castle casting news, Victor Webster will recur this season as Beckett's new love interest.

The show returns on September 20.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.