Sam Smith Reveals He Was 'So Scared' About Oscars Performance

The singer won Best Original Song for "Writing's On the Wall" from "Spectre."

— -- Sam Smith, the man with the golden voice, now holds the ultimate prize in the movie world: Best Original Song for "Writing's On the Wall," from the James Bond film "Spectre."

“Winning something like this, honestly it feels unbelievable,” Smith told “Good Morning America’s” Robin Roberts backstage. “It just feels incredible.”

“This award tonight means so much to us,” Smith said backstage of his win with Jimmy Napes.

“We're English too. So to work on Bond is a dream come true,” Napes added.

Smith told Roberts that the duo did not set out to write a song for “007” -- it happened organically.

"It’s actually our first song that we didn't write from my perspective," Smith explained.

“The way the song was created in such an organic way, it wasn't planned, we didn't sit down and say, ‘We're going to write a Bond song.’ We were actually recording something completely different the day we wrote the song,” Smith said. “For me, it's given me complete faith in what we do. And in the future to just to carry on and keep it organic, honest and as real as we can.”

The Oscar winner wowed with his live performance of "Writings on the Wall," but revealed he was shaking and overcome with nerves.

“The performance … was one of the worst moments of my life,” Smith said. “I didn't get any enjoyment out of that performance. I was just so, so legs were shaking. I could have peed myself I was so scared.”