LONDON -- Singer Lorna Luft, the daughter of Judy Garland, was undergoing tests in a London hospital following an initial diagnosis of a brain tumour after she collapsed backstage at a concert in London.

The singer's representative, Victoria Varela, said the 65-year-old Luft collapsed backstage on Friday night and was rushed to the hospital, where she was given an initial diagnosis of a brain tumour.

Varela says the singer's husband, Colin Freeman, had been concerned that she was forgetting lyrics and a monologue. Luft was undergoing further tests at London's Chelsea and Westminster Hospital.

 Varela says Luft has been in remission from breast cancer, which she has been battling for six years.