TV and stage actress Joanna David was diagnosed with a brain malformation and underwent surgery in 1992 at the National Hospital for Neurology and Neurosurgery.
The 67-year-old, married to Edward Fox, said she owed her life to the centre in Queen Square, which was still in “desperate” need of funds.
The National Brain Appeal, which has raised £40million and marks its 30th birthday today, is appealing for £3million to build an additional operating theatre.
Mrs David, a charity trustee, said: “Facing brain surgery has to be one of the most terrifying experiences and it was hugely reassuring to know I was in such good hands. With both my personal experience and the knowledge that this is an area of desperate need, I felt compelled to support The National Brain Appeal to help ensure that the hospital has all the support it needs.”
Her daughter, Silent Witness actress Emilia Fox said: “Without The National Hospital I might not have a mum.
“Thank you with all my heart National Hospital and The National Brain Appeal. As a family, we are eternally grateful to all the wonderful people who work there.”
Her brother Freddie Fox, who starred opposite Rupert Everett in play The Judas Kiss, added: “The National Brain Appeal means everything to me.
“It supports the hospital that saved my mother and I’m in continual admiration for the amazing results both the hospital and charity achieve.”
Actor Stephen Mangan, known for his roles in Green Wing and Episodes, started supporting the charity after losing his father to brain cancer almost 10 years ago.
He said: “Brain cancer is a devastating disease. The 10-year survival rate, in spite of doubling in the last 40 years, is still just 13 per cent.
“New and more effective treatments are desperately needed.
“The National Brain Appeal charity has funded several vital projects to enable our leading specialist brain tumour doctors and surgeons to develop new treatments.”