Boyband star Lee Ryan and model Casey Batchelor, former The Apprentice star Luisa Zissman and retired boxer Evander Holyfield, are up for eviction from the Channel 5 reality show.
N-Dubz rapper Dappy and columnist Liz Jones were the first pair to be put up for eviction on Friday's launch, after being set free from their handcuffs.
Host Emma Willis opened the show, saying: "Nothing is as easy as it seems.
"They might be living in luxury but they can't escape the shackles of celebrity."
During the weekend, housemates competed to win immunity from the first public vote - and freedom from their "shackles".
The Only Way is Essex star Sam Faiers and her partner Jasmine Waltz earned their way out of the handcuffs, by being the pair who knew the most about the other.
Sam and Jasmine guessed four answers correctly - narrowly beating the other pairs who all gave three answers.
Comedian Jim Davidson and singer Linda Nolan were also separated after they won the Building Blocks of Celebrity task.
The celeb pairs were asked to build a tower which represented the reasons why they were famous.
All the shackled celebrities reached the same level of fame, so Big Brother asked them to vote on who they felt deserved their freedom.
The contestants unanimously chose Jim and Linda to be freed.
Veteran entertainer Lionel Blair and Made In Chelsea star Ollie beat off the competition in the Tangle task, leaving Evander and Luisa, and Casey and Lee, facing the public vote.
Voting lines open after tonight's show.