Bonnie, Glyn and Dawn are the first Big Brother housemates nominated for eviction from the seventh series of the Channel 4 reality show.
Bonnie, the 19-year-old care worker from Loughborough, is the bookmakers' favourite to go on Friday, at odds of 1/3.
Exercise scientist Dawn threatened to walk out when her name was read out, and Welsh lifeguard Glyn, 18, is also up for eviction.
Meanwhile, former contestant Shahbaz Chauhdry admitted he had "spectacularly fallen apart" inside the TV house after just five days inside. He walked off the show on Tuesday night.
He said other housemates had portrayed him as the "wicked witch" and that fellow homosexual contestant Richard wanted to be "the only gay in the Big Brother village".
Shahbaz told Dermot O'Leary on 'Big Brother's Little Brother' that he had no other choice but to quit while he was ahead.
"I never saw my breakdown coming but wasn't it spectacular everyone? Car crash TV at its finest."
