A patient at a British hospital played Mahler and Gershwin on the violin while a tumour was removed from her brain.
Dagmar Turner performed the act so that surgeons could preserve her ability to play music.
The 53-year-old former management consultant from the Isle of Wight was diagnosed in 2013 with a slow-growing tumour after suffering a seizure during a concert.
She had radiotherapy to treat the tumour but, when it became more aggressive last year, she decided to undergo surgery to have it removed.
Ms Turner played her violin during an operation to remove a tumour from the right frontal lobe of her brain.
That area is close to the part of the brain that controls the fine movement of the left hand.
To prevent any damage to her violin skills, Professor Keyoumars Ashkan, Consultant Neurosurgeon at King's College Hospital, came up with a plan.
They would map her brain, open the skull and then get her to play as they removed the tumour.
While surgeons cut away part of her brain, Ms Turner played music by Gustav Mahler, George Gershwin's jazz classic "Summertime" and pieces by Spanish songwriter and singer Julio Iglesias.
"This was the first time I've had a patient play an instrument," said Prof Ashkan.
"We managed to remove over 90% of the tumour, including all the areas suspicious of aggressive activity, while retaining full function in her left hand."
Ms Turner thanked the surgeons.
"The violin is my passion; I've been playing since I was 10 years old," she said.
"The thought of losing my ability to play was heart-breaking.
"Thanks to them I'm hoping to be back with my orchestra very soon."
Ms Turner, who has a 13-year- old son, underwent the procedure last month.
She left the hospital three days after the surgery and will continue to be monitored by her local hospital.