In a dramatic twist in Monday night's (July 29) show, the housemates were all shown each other's nominations on a big screen.
Callum was nominated for eviction with the most votes and will battle Dexter Koh, Hazel O'Sullivan and Jack and Joe Glenny in the public vote on Friday.
However, the sports coach currently appears more concerned by the revelation that Charlie voted for him.
"I'm surprised, not disappointed. Now I know how you feel," he told her.
"Tonight I learnt something which is the way you view me. You have lost in me your biggest fan in the house.
"You have lost someone who has fought your corner and would never ever let you down."
Big Brother continues daily on Channel 5.