Julie Chen returns as host of "Big Brother 11."

“Big Brother” goes green (with an eco-friendly house) and mean (forcing the houseguests back into high school cliques) for Season 11, CBS said Wednesday in announcing the 12 people who will compete as “popular, athletes, brainiacs and off-beats.”

“What group did you fit into in high school? ” the network asks, promising that this season’s 12 strangers (plus a 13th, mystery houseguest to be named later) will be “shocked to learn that they will compete for food, safety from eviction and luxury prizes as part of their clique.”

“You may have graduated, but the truth is we never leave high school and this summer we are going to prove it,” says executive producer Allison Grodner. “From the brains to the jocks to the off-beat, everyone will be able to identify to one of these cliques, giving the viewers a group to root for and against from the very beginning. The division will cause instant drama.”

These are the 12 houseguests announced Wednesday.

Braden Bacha, 28
Santa Monica, Calif. 
Single
Surfer   

Casey Turner, 41
Lakeland, Fla.                                            
Married father
Fifth grade teacher

Chima Simone, 32
West Hollywood, Calif.
Single
Freelance journalist

Jeff Schroeder, 30
Norridge, Ill.
Single
Advertising salesman

Jordan Lloyd, 22 
Matthews, N.C.
Single
Waitress

Kevin Campbell, 29
Chula Vista, Calif.
Single
Graphic designer

Laura Crosby, 21
Atlanta
Single
Bikini model

Lydia Tavera, 24
Torrance, Calif.
Single
Special effects makeup artist

Michele Noonan, 27
Pasadena, Calif.
Married
Neuroscientist

Natalie Martinez, 24
Gilbert, Ariz.
Single
Tae kwon do champion

Ronnie Talbott, 30
Belpre, Ohio
Married
Gamer

Russell Kairouz, 24
Walnut Creek, Calif.
Single
Mixed martial arts fighter

About that green house:

“The houseguests will live and compete in a house that has been transformed into a mean, green, eco-friendly living machine. The interior walls of the house are covered with a reconstituted wood panel product made from reclaimed wood flakes.  This eco-friendly material reduced the amount of new lumber used to build the “Big Brother” house.  For the first time ever, the houseguests will be made fully aware of the amount of waste they create, and will be required to sort, recycle and place all food items in an outdoor manual compost center, as well as an indoor automatic composter.  The Head of Household Suite feels like seaside in Big Sur, Calif., where actual driftwood hangs on the copper patina tinted walls while a working waterfall, using recycled water, trickles over stacked stone to serve as a headboard.  Zebra wood columns (all faux wood) press into the room framing a contemporary window that overlooks the “surf.”

“Big Brother 11″ premieres at 7 p.m. Thursday and will air three nights a week — 7 p.m. Sunday, 8 p.m. Tuesday and 7 p.m. Thursday for the live eviction show. Julie Chen returns as host.