While the hapless HMs may have expected one intruder to join their ranks, this evening BB delivered three new – and one old – Housemate plus one Houseguest to the BB compound.

Earlier in the evening, BB kicked off the festivities with a party.

“Big Brother is throwing a party,” BB announced. “You are all invited. After this week’s Eviction, the average age of the House became significantly lower. BB thought it would be fitting to have a children’s party. Housemates, all good parties have big surprise.”

The Housemates all ran for the backyard and where they discovered a game of Twister, a piñata, cupcakes, party hats and decorations. The HMs didn’t waste a moment getting into the party spirit, putting on their hats and digging into the sweet treats.

Travis and Alice made a beeline for the piñata, and Travis spun Alice in wild circles to disorientate her before unleashing her on the thong piñata.

Big Brother gave the Housemates a small insight into the night’s proceedings by giving a refresher course on the audition process. As the penny dropped with Rebecca, she waved three fingers around, realising they would be welcoming three brand new Housemates to their abode.

“The three people chosen by the Australian public represent your biggest threat,” boomed Big Brother. “They will enter your House tonight.”

The gates into the backyard swung open, and the Housemates welcomed their first new Housemate of the evening, lifesaver Barney. Rebecca was the first HM to rush to Barney and introduce herself, and the rest of the Housemates offered hands to shake and names for Barney to remember. Looking slightly overwhelmed, yet with a massive smile on his face, Barney attempted to take in his new surroundings.

“I think you’ve got a crush,” Rebecca jibed Brigitte. “He looks like Greg Brady!” exclaimed Brigitte, while Alice stood by, cheekily smiling to herself.

Ben took the opportunity to fill in Barney on what he’s missed over the past week. He covered the Surprise Snap Eviction, the dining room conveyor belt, and the reveal of the brand new kitchen.

The introduction chatter came to an abrupt halt as Big Brother announced the Housemates were to meet their next biggest threat – new Housemate Nathan.

“How you doing guys?” exclaimed Nathan, as he entered the backyard before vigorously greeting his new Housemates. Saxon’s interest was piqued when he overheard Nathan tell another Housemate he’s an Adelaide boy.

Saxon bailed him up immediately with the most pressing question of the evening: “Are you Power or Crows?” he demanded.

Travis introduced himself to Nathan with a hug, while Saxon and Rory offered to give their new Housemate the grand tour. As Nathan took a room-to-room inspection of the Big Brother House, the remaining Housemates spouted theories back and forth as to who the final new Housemate would be. All bets were on another girl to join the House – but if the HMs were to have backed up their wager, they would have lost big, for they were wrong.

But Big Brother’s massive surprise was still to come…

Who was the final Housemate to walk through Big Brother’s gates?