The Ex On The Beach star was also told to spend the night by himself in the spare room after throwing a mug against a wall during a row, which damaged a mirror.
In scenes to air on Thursday night (4 August), we'll see Bear becoming embroiled in an argument with Heavy D. It all starts when Bear and Chloe Khan are dared to kiss, and then keep on doing it in the bathroom while the other housemates try to sleep.
Heavy D gets annoyed and tells Bear: "I'm trying to get some sleep mate, what's wrong with ya? It's 2am in the morning!"
Bear argues with him, leading Big Brother to call Heavy D to the Diary Room in a bid to calm him down. Heavy D reckons Bear has no respect for the housemates who are trying to sleep.
Back in the bedroom, Renee Graziano tells Bear that he has "belittled" housemate Heavy D, which annoys Bear. So he heads off to the garden alone, picks up a mug and smashes it against a wall, damaging a mirror.
Big Brother then calls Bear to the Diary Room and tells him that was unacceptable behaviour and won't be tolerated. An angry Bear brands that decision a "joke" but Big Brother definitely is NOT joking, informing him he'll be sleeping in a separate room from the housemates.
Bear becomes increasingly annoyed when he asks Big Brother to let him out of the Diary Room but they refuse. Security ends up intervening to ask Bear to sit down quietly, which he does, apologising to Big Brother for his actions.
It's again reiterated that Bear's behaviour is unacceptable and he's been given a formal warning.
Bear's the second contestant this series to have a formal warning. Aubrey O'Day was given one this week after she spat in Bear's tea and sandwich, which he consumed unaware it contained her bodily fluids.
CBB continues 9pm on Channel 5.