Anthony Kulkamp Dias from Brazil has accomplished one amazing guitar feat to brag about to his friends, and it's a safe bet that none of them can top that.

Previously, the 33-year-old banker did the unthinkable during a surgical procedure aimed at removing tumor from his brain. Well, Dias played his guitar and sang along to The Beatles' classic "Yesterday."

The surgery team, which performed the operation at the Nossa Senhora de Conceição Hospital in the southern state of Santa Catarina, had to make sure he was awake during the operation to chart his responses. The team had to see that the delicate procedure won't compromise his speech and movement, the Daily Mail reported.

Dias, who has been a professional musician for 20 years, decided to do his thing and opened his cognitive test-mini concert with a song called "Emanuel." He wrote the song for his newly-born son.

Then, he played the hit song written by John Lennon and Sir Paul McCartney before going through at least three other Brazilian country songs.

"I played six songs at determined moments," he said. "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."

The hospital's clinical director, Dr. Jean Abreu Machado, said that conducting the procedure on a conscious patient allows mapping of important areas of the brain, monitoring them in real time, the Telegraph noted. Machado added that while the brain tissues don't feel pain, the skin and "other structures" would.

The anesthetist, meanwhile, is tasked to maintain the patient's consciousness and keep the latter from pain.

Prior to his diagnosis, Dias said he stammered with his speech, and became really forgetful of things that he could not even remember the make of his very own car, the New York DailyNews said. The tumor was found half-a-month after his son was delivered a few months ago.

And the best part about his performance? Our guitar man said he was asked by the doctor to do a repeat of one of the country songs he played. This was one of those ways his doctor can check on his responses. But, for musicians like him, to be asked by your audience for an encore... now, that's saying something.

Congratulations Anthony, both for the successful surgery and O.R. gig!