Big Brother always prepares its viewers to expect the unexpected!

On Thursday, Big Brother's official Facebook page posted a headline from which read: "Julie Chen to Reveal Game-Changing Element on Big Brother After Show Tomorrow."

The After Show, hosted by former Big Brother and The Amazing Race contestant Jeff Schroeder, airs Fridays on CBS All Access, the network's online video subscription service. 

CBS declined to reveal any additional details about the new twist -- including whether it may possibly have a connection with this Friday's night first-ever "Battle Back" competition between the previously evicted houseguests or an end to this season's "Team Play" format.

For the "Battle Back" competition, the first five evicted Big Brother 18 houseguests will compete for a chance to re-enter the game. The first four evicted houseguests have been Glenn Garcia, Jozea Flores, Victor Arroyo and Bronte D'Acquisto. The final eliminee who will compete for the opportunity to come back will be determined via tonight's live eviction episode.

Big Brother 18's season began with a format that divided the 16 initial houseguests in four four-person teams. However while the houseguests have competed for Head of Household individually, all the team members of each week's reigning HoH have automatically been safe from nomination for eviction -- a limitation which has increasingly limited the season's gameplay and denied houseguests the opportunity to target members of their own teams.

The Big Brother season's original teams are listed below:

- Category 4: Returnee Frank Eudy, Michelle Meyer, Paulie Calafiore and Bridgette Dunning.

- Big Sister: Returnee Da.Vonne Rogers, Paul Abrahamian, Zakiyah Everette and Jozea Flores.

- Freakazoids: Returnee Nicole Franzel, Corey Brooks, Tiffany Rousso and Glenn Garcia.

- Team Unicorn: Returnee James Huling, Natalie Negrotti, Victor Arroyo and Bronte D'Acquisto.
About The Author: Elizabeth Kwiatkowski
Elizabeth Kwiatkowski is Associate Editor of Reality TV World and has been covering the reality TV genre for more than a decade.