The 33-year-old model blasted Perez, after the blogger, 36, accused him of playing a game.
Perez claimed he was playing peacemaker to win popularity, causing Calum to fume: "I am a genuine, honest chilled out person.
"Nobody likes you because you act like a d*ckhead. I am the same inside this house as I am on the outside."
After managing to hold back for so long Calum lost it, continuing: "[You have] 72 different characters, and play up to the Perez show and this is why no one in this country likes you."
Unsurprisingly Perez wasn't ready to leave things there, telling Calum they'd never been friends and that he didn't like him.
Calum snapped: "Shut the f_ck up you f_cking power tripper. You're a piece of sh*t and nobody likes you!
"Don't bother talking to me for the rest of the time, you c***!"
Later in the diary room, Calum admitted that his argument with ‘farce’ Perez had been caused by built up tension.
He said: “Little things can spark into big things. I’m a closed book… And that’s how I am. Some people are real and some people are full of it.”
Calum's rant caused divided opinions on Twitter. One user wrote: "Calum just being an arse there. Perez wasn't saying anything wrong just sharing views [sic]"
But another said: "After tonight's ep Calum has got to be in with a chance of winning. His home truths for Perez were spot on."
From reality TV to fatherhood: Calum Bestu2019s life in pictures
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Calum Milan Best
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Born February 6 1981.
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He was born in Malibu and raised in LA. He moved to London when he was 21.
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Calum is the son of the footballer George Best and model Angie Best.
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His father George died in 2005 aged 59, after suffering from multiple organ failure.
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He rose to prominence when he appeared on the ITV reality show Celebrity Love Island in 2006.
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Calum is well-known for being a ladies’ man, having had relationships with many high profile women.
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He and model Jodie Marsh dated for four months in 2003.
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In 2005 he dated Girls Aloud star Sarah Harding. They were together for around two years. Last year he revealed they once spent three days in bed together.
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Things got steamy between Calum and David Beckham’s former PA Rebecca Loos while they were both on Celebrity Love Island.
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He met Bianca Gascoigne while on Love Island, and they are believed to have had a short relationship after the show.
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In 2006, Calum had a short relationship with model Lorna Hogan. She fell pregnant and gave birth to their daughter Amelia Lucie Hogan.
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Calum and Hollywood actress Lindsay Lohan briefly dated in 2007.
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In 2013 Calum admitted to cheating on model Georgia Salpa with presenter Donna Air.
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MTV’s Totally Calum Best debuted in 2008, which saw Calum attempt to remain celibate for 50 days and 50 nights.
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Calum filed for bankruptcy in 2013, saying at the time: “I can confirm I have made the decision to declare myself bankrupt as a result of being unable to make tax repayments.”
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Calum filmed scenes for the lead role in the movie Countryman in 2014. He also appeared in adverts for Rolls Royce in Dubai.
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In November that year, Calum underwent his third £6,000 hair transplant.
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He’s tipped to enter the Celebrity Big Brother house in January 2015.