The former EastEnders star, who was up against all the other housemates in the public vote, is the fourth contestant to be voted out of this series.
Brian Dowling announced the eviction to an eerie silence, with the crowd absent due to the bad weather.
The other housemates gasped in surprise when Gillian was named.
When she had gone, Tricia Penrose said: "I feel like crying."
Gillian had come third in the Digital Spy readers' poll on who should be evicted next, with Heidi and Spencer and Tricia Penrose in first and second place.
She will allegedly meet up outside the house with boyfriend Dave Fairbairn, a former 'drug baron'.
Photo gallery - Celebrity Big Brother day 15: