More residents of the "Beverly Hills, 90210" spinoff have been confirmed.

The world's most famous zip code is quickly filling up! ET confirms that two new cast members are joining the "Beverly Hills, 90210" spin-off. JESSICA WALTER, who played the family matriarch on the critically acclaimed "Arrested Development," is set to play Tabitha, grandmother to newly announced cast member SHENAE GRIMES ("Degrassi: The Next Generation") and mother-in-law to LORI LOUGHLIN's ("Summerland") character.

Also newly announced, "Dirt" star RYAN EGGOLD has been tapped to play a teacher -- who also happens to be named Ryan.

The as-yet-untitled show will, like the original, center on a family (this time it's the Mills instead of the Walshes) who moves from the Midwest to Beverly Hills and will revolve around the clan's two teen kids -- a boy and a girl -- who are the same age.

The Mills -- Celia, a former Olympic medalist, and Harry Mills, a Beverly Hills High alumnus who moved after graduation to East St. Louis -- return to the infamous zip code after his alcoholic 1970s movie star mom begins to spiral downward. Along for the ride: their biological daughter, Annie, and adopted son, Dixon.

Here is the breakdown of the cast so far:

Shenae Grimes -- Annie Mills
Lori Loughlin -- Celia Mills
ANNALYNNE McCORD -- Naomi, who is hot, rich and one of the most popular girls in school
DUSTIN MILLIGAN -- Ethan, a "likable, genuine ... star athlete."

And while none of these kids appear directly related to characters from the original series, it is nevertheless curious that 16-year-old Daphne Silver and her older brother, Max Silver, have the same last name as David Silver (BRIAN AUSTIN GREEN), who married Donna Martin (TORI SPELLING) in the '90210' series finale.