Davina McCall pictured in 2019Davina McCall has shared that she is undergoing brain surgery after doctors discovered a rare tumour.On Friday morning, Davina posted a pre-recorded video message on Instagram, telling her followers that a benign brain tumour had been discovered during a health check earlier this year.“A few months ago I did a menopause talk for a company, and they offered me a health scan in return, which I thought I was going to ace,” the former Big Brother host began.“But it turned out I had a benign brain tumour called a colloid cyst, which is very rare.“I slightly put my head in the sand for a while, and then I saw quite a few neurosurgeons. I got lots of opinions and I realised that I have to get it taken out. [The tumour] is big, for the space, it fills the space, it’s 14mm wide and it needs to come out because if it grows, it would be bad.“So, I’m having i