A Slovenian opera singer undergoing brain surgery remained awake during the procedure, serenading his doctors.

As doctors worked on Ambroz Bajec-Lapajn’s exposed brain, they encouraged him to talk and sing to be sure the surgery would not hinder his ability to sing, Fox News reports.

A Youtube video of the surgery shows the tenor singing Franz Schubert’s “Gute Nacht” during the procedure last year at the University Medical Center Utrecht in the Netherlands.

“It’s been more than a year since [the operation], and I’m doing fine, continuing my professional singing career,” Bajec-Lapajne wrote on his YouTube video posting.