An astonishing video shows the moment a Brazilian man started playing “Yesterday” on his guitar while undergoing brain surgery.

Anthony Kulkamp Dias, 33, was having a brain tumor removed last week when he started playing the classic Beatles tune, reports The Guardian.

Kulkamp, who is said to have played guitar professionally for 20 years, also played a song entitled “Emanuel,” which he wrote for his newborn son, and other songs during the operation.

“I played six songs at certain times,” Kulkamp told local media of the surgery, per The Telegraph. “My right hand was a bit weaker because that was the side that they were operating on. So I stopped and rested. I was interspersing songs and talking with them.”

Kulkamp was reportedly kept conscious during the surgery so as to enable doctors to safely map the brain, allowing them to avoid injuring the organ in a way that would compromise important functions later on.

Since the brain has no pain receptors, keeping patients conscious during surgery is not entirely unusual.