Cast updates: Waifs on TV!

Paparazzi princesses guest-starring on network comedies was a late trend in television last season, with Britney Spears popping up on How I Met Your Mother, Paris Hilton landing a dream role (literally) on My Name is Earl, and Lindsay Lohan lending her likeness to Ugly Betty.

Most of the experiments paid off somewhat, if not in ratings then in publicity. It appears that trend is already seeping into the upcoming fall season, as two camera-friendly ladies have stopped club-hopping for enough time to commit to guest stints on high-profile comedies.

Former Paris BFF and new mom Nicole Richie is returning to television via NBC's action-comedy Chuck, the network announced. She'll play the high-school nemesis of Sarah Walker (Yvonne Strahovski), and come into play when Chuck (Zachary Levi) and Sarah attend the latter's 10-year high-school reunion.

Wondertwin Mary-Kate Olsen, fresh off her recurring role on Showtime's Weeds, will once again guest star in a show about memory loss. Olsen has signed on to do one episode of ABC's Samantha Who?, according to E! Online, and will play a character that Samantha (Christina Applegate) tries to "save."

Battlestar Galactica's Tricia Helfer has settled on a project once the Sci Fi Channel show ends its run. The statuesque actress, who also has a recurring role on USA Network's Burn Notice, has been cast in the Fox pilot Inseparable, says The Hollywood Reporter. The drama is about a modern-day Jekyll-and-Hyde-type character (played by Viva Laughlin's Lloyd Owen) who is part forensic psychiatrist, part criminal. Helfer will play a police psychiatrist who evaluates bad guys.

FX's Damages is adding some firepower with the casting of Deadwood alum Timothy Olyphant. The brooding actor recently played bald assassin Agent 47 in Hitman, and was previously featured in Go and Gone in 60 Seconds. On the critically lauded legal drama, Olyphant will play a character that gets involved with Ellen Parsons (Rose Byrne).

Law & Order: SVU has found a new assistant district attorney. Michaela McManus (One Tree Hill) will replace Diane Neal as the new ADA next season, says The Hollywood Reporter.

Elsewhere, Laurie Metcalf has joined the CW's Easy Money, Hart Bochner has been added to USA's The Starter Wife, and Anne Archer is now part of Privileged, the CW teen-oriented drama that was previously titled Surviving the Filthy Rich and How to Teach Filthy Rich Girls.

Like on Facebook