Josie was the first to arrive in the house, just 20 minutes after winning Big Brother 11.
She laughed as she walked back down the stairs singing to the Backstreet Boys' 'Everybody (Backstreet's Back)'.
Next to enter was Chantelle Houghton, who made headlines when she became the only non-celebrity to not just enter the Celebrity Big Brother house, but also win the series. She hugged Josie as she walked in, telling her: "Congratulations."
Third in was Samuel Preston, aka Preston, former Celebrity Big Brother contestant and lead singer of The Ordinary Boys.
Chantelle looked shocked to see her ex-husband as he entered the house, telling him that she was shaking. The pair seemed to be on good terms though, and gave each other a hug.
Winner of BB5 Nadia Almada then entered. "Hello there, you randy mare!" she said as she hugged Josie.
Next up was Brian Dowling, who won BB2 in 2001 with 69% of the public vote. Upon seeing Nadia in the house, Brian shouted: "I knew you'd be here! I can't fucking get rid of you!"
"If you're coming in I'm going out!" Nadia jokingly replied.
The fifth Ultimate Housemate to enter was Ulrika Jonsson, who received a negative reaction from the crowd. She congratulated Josie as she greeted her, saying: "My 10-year-old said, 'If you go in there, you could be Josie's best friend!'"
Makosi Musambasi, from Big Brother 6, was the sixth to arrive. Although she was one of the favourites to win the show in the first five weeks, she finished the series in third place with 8.9% of the public vote.
The seventh to be revealed was John McCririck, from Celebrity Big Brother 3. Most of the other entrants have named him as the person they would least like to share a house with. John said that he has no intention of trying to win and walked in with a sign that read: "Evict me please!"
Rap artist Coolio was the eighth to re-enter the house. He took part in Celebrity Big Brother 6.
Nikki Grahame was next up. She told Davina that she has grown up and 'hasn't had a tantrum' since appearing on Big Brother 7. She looked nervous as she walked down the steps to greet her housemates and congratulated Josie with a hug.
The last Ultimate Big Brother housemate to enter was 'Nasty' Nick Bateman. Nick personified the pantomime villain in the house when he was asked to leave Big Brother 36 days into the very first series for trying to manipulate fellow housemates' nominations.