The claustrophobic CBS reality show is sealing 13 actual strangers -- no ex-lovers, secret twin partners or long-lost siblings this time -- inside a makeshift house on a Studio City soundstage for the chance to be the last houseguest standing and take home the $500,000 grand prize. "Big Brother" has its season premiere at 8 p.m. Sunday.

"There's somebody for everyone in this cast," executive producer Allison Grodner said. "It's going to be interesting to see people that come from such opposite worlds living together, which has always been a part of this show, but this season, we really do have our most diverse group ever."

The contestants -- which will include a gay bull rider, a Hooters waitress, a professional bodybuilder and a 75-year-old former Marine -- will spend about three months this summer competing in challenges and evicting each other while being monitored by more than 50 cameras. It's the first time since the show's third season that the houseguests are all strangers.

"When approaching this season, we wanted to look at what made this spark and last for 10 seasons," said Grodner, who has worked on "Big Brother" since the second season. "Every season had its unique twist. I think, in a way, going back to basics and having the cast be all strangers is part of the twist of '10.' Of course, there will be more."

In last season's first winter edition of "Big Brother," which was quickly put into production because of the writers' strike, contestants were partnered with each other and evicted as pairs for the first four weeks of competition. Grodner said a new "Big Brother 10" gameplay twist would be introduced during the premiere episode.

"It's really a power-play," teased Grodner. "The game will actually start before they enter the house."

In recent seasons, contestants have come under fire outside the house for controversial remarks made inside the house. During the eighth season, Amber Siyavus said that Jewish people tend to be "really money-hungry" and "selfish." Last season's winner Adam Jasinski was fired by a nonprofit autism organization because he used the word "retards."

"Those types of comments are not something we want to happen," said Grodner. "It's a live show. It's not censored on the Internet. These are real people. We aren't telling them what to say, but we're not telling them what not to say either. Things do happen. We, of course, can choose what we put in the show, and we do so carefully."

This season's contestants seem to be more aware of the repercussions of their actions from the outset.

Before meeting their competitors or entering the house, the "Big Brother 10" cast was individually interviewed by the AP while they were voluntarily sequestered -- no television, newspapers or telephones -- from the outside world in a Studio City hotel.

"If you make a mistake and say the wrong things, you may offend people and be known for that forever," said Steven Daigle, a 35-year-old geographic consultant and gay rodeo competitor from Dallas. "People make mistakes. If I do make a mistake, I hope I can learn from it and know that was some part of my life that I was ignorant or uneducated about."

The rooms inside the "Big Brother" house this season will be themed to different decades. The kitchen, for example, resembles a '50s diner while one of the bedrooms is filled with '70s-inspired furnishings. The timeliness extends to this season's crop of contestants. At 75, Jerry MacDonald will be the oldest "Big Brother" houseguest ever.

"Age does not bother me," MacDonald said. "I hope it doesn't bother them."

Libra Thompson, a married 31-year-old human resources representative from Spring, Texas, left behind her husband and three children -- including 4-month-old twins -- to participate in "Big Brother 10." During production, Thompson and the other "Big Brother" contestants are prohibited from communicating with the outside world.

"It's better for me that they're younger," said Thompson of her newborns. "At 4 months old, they're not going to remember much. It's probably going to be a little bit more difficult for my 4-year-old. However, I'm going to stay focused and remember the reason I'm here, and that's the cash. That will help me."

First Published: July 11, 2008, 8:00 a.m.