The summer has officially begun, which means Big Brother is in full swing!

Entering its 17th installment (can you believe it?!), CBS’ long-running summer staplefeatures a new crop of houseguests -- 14 of whom were revealed last week -- with a never-before-seen twist that will surely keep them on their toes.

“They’re a really diverse group of people -- a lot of layers to who they are -- and we’re looking forward to those stories coming out in the house over the course of the summer,” executive producer Rich Meehan tells ETonline ahead of Wednesday’s premiere. “We’re optimistic [about this group].”

PHOTOS: First Look at the Brand-New 'Big Brother 17' House!

One houseguest making headlines is Audrey Middleton, a 25-year-old digital media consultant from small-town Georgia, who is the first transgender contestant to compete on Big Brother. A self-proclaimed Big Brother fan, Audrey’s inclusion in the cast was borne organically -- in fact, she applied “early in the process,” executive producer Allison Grodner tells ETonline.

“Honestly, she would have been cast whether she was transgender or not,” Grodner adds. “She is fabulous. We love her, and we’re excited that we’ll ultimately have our first transgender [houseguest] in Big Brother history this season.”

Grodner reminds viewers that there is more to Audrey than being transgender, emphasizing that “that’s not everything she is.” Last week on The Talk, Big Brother host Julie Chen teared up while discussing Audrey, asking viewers to watch the season with “compassion" and with an "open mind." Grodner is equally hopeful viewers will respond to Audrey, describing her as “charismatic, bright and a strategic player too.”

This season's big twist is “BB Takeover,” a new weekly concept that will bring on one special guest to introduce that week’s stunt. (Because the premiere kicks off with a two-night event, two guests will be featured.)

WATCH: Take a Tour of the 'Big Brother 17' House With Host Julie Chen

“Every week, a new surprise guest will be revealed on our live show and they will take over the game and twist it up,” Meehan explains. The surprise guests will vary depending on the theme of the week -- from well-known Big Brother fans, including celebrities, to “familiar faces,” though Grodner would not elaborate.

The past three seasons have featured a cast of 16 and with this year’s crop only listing 14, there’s a very specific reason why. The last time Big Brother featured a cast of just 14 houseguests was back in 2011, during season 13.

“It could be anything, so tune in to the premiere to find out. You’re on to something in the number though,” Grodner hints. “We haven’t had 14 in a long time.”

Season 17 has one of the youngest median ages in recent years, with an average houseguest age of 26 ½ years old. The oldest houseguest this season is just 33.

PHOTOS: Meet the New 'Big Brother 17' Houseguests!

“We don’t set out to say we have to hit a specific age. We just go out and we cast a wide net,” Meehan explains, when asked whether it was their intention to continue to go younger this season. “We look for really unique people and when we look at our mix of people we choose who we think will be best in the house. Sometimes there are people in their 40s who make it in, sometimes there’s not.”

After being at the helm for more than a decade each, Grodner and Meehan have seen it all -- and then some. Even so, they have high hopes for the new season.

“One of the great things of Big Brother and why we’re going into our 17th season is every season is different, every summer is different. Different strategies win the game, different types of people win the game,” Meehan says. “What would be great for us is to see something we’ve never seen before. That would be the best-case scenario.”

“Expect the unexpected, and that goes for us too,” Grodner adds.

NEWS: 'Big Brother' Production Designer Dishes on the Bigger House

Whether that includes an all-star edition remains to be seen. There is currently no timetable for the next full-fledged all-star season, something longtime fans have been waiting since season seven for.

“Right now we’re in the accumulation of all-stars phase and once we feel like we have a group that [justifies it] -- if we’re going to do an all-star season we want to make sure that there’s something that makes it different,” Meehan says.

Adds Grodner: “Everyone’s seen an all-star season on these shows, including ours, and we want to make sure that when we do an all-star season it’s new, it’s fresh and we have the best group possible.”



Big Brother debuts with a two-night premiere on Wednesday, June 24 and Thursday, June 25 at 8 p.m. ET/PT on CBS.

To find out why Julie Chen got emotional talking about Audrey Middleton, click play on the video below.