Big Brother 27: Will the 17th Houseguest Compete for the Prize?

It’s been a wild week in the world of Big Brother. After officially revealing the Big Brother 27 cast, CBS dropped another bombshell — the AI Arena is back, and so is the mystery. With the 90-minute premiere airing tomorrow night, followed by a second episode on Sunday, fans are buzzing with anticipation. But the biggest question heading into the premiere? Who is the 17th Houseguest?

Weeks ago, producers teased that surprise guests would shake things up in the opening episode. We’re expecting a masked visitor, an accomplice, and now — a mystery Houseguest. At first, it was unclear if this would be just a quick cameo to support the season’s “Summer of Mystery” theme or someone actually joining the competition for the $750,000 grand prize.

However, recent interviews with Julie Chen Moonves suggest something much bigger. Julie hinted that this mystery houseguest would be a divisive figure, someone who’s bound to stir up reactions — both inside and outside the house. Her tone made it pretty clear: this isn’t a one-time twist. This person is very likely the 17th official Houseguest.

During her Entertainment Tonight house tour, Julie confirmed even more. She explained that the new players will have to decide whether to align with or target this individual. Some may be frustrated by the surprise twist, but Julie thinks most will be star-struck. She also noted that this person will bring valuable game knowledge and the others may be eager to learn from them. That strongly suggests the mystery guest is not a newbie — but rather someone with deep Big Brother roots.

Read More: Big Brother 27 Has Begun — Houseguests Checked Into “Hotel Mystère”

Naturally, speculation is running wild. Could it be a celebrity, a reality TV icon, or more likely — a returning former Houseguest? Based on Julie’s clues, many fans are now convinced the mystery player is none other than Rachel Reilly.

Rachel checks all the boxes: big personality, polarizing presence, and a wealth of experience. A list of Instagram clues compiled by Hamsterwatch on Bluesky points directly at her. Meanwhile, her husband Brendon Villegas has been actively denying the rumors — but fans think he might just be covering for her (and possibly running her accounts while she’s in sequester).

Even Janelle Pierzina chimed in, revealing that Rachel hasn’t returned her calls — although she’s supposedly “on vacation.” Suspicious? Very.

At this point, all signs seem to lead to Rachel Reilly re-entering the Big Brother house as the 17th Houseguest. If true, this would mark a major twist in BB27 — and one that could dramatically shift the game dynamics from Day 1.

We’ll find out for sure when the Big Brother 27 premiere airs Thursday at 8/7c on CBS. Stay tuned!