Some of the biggest names in music have shared the stage with Paul McCartney, from Bruce Springsteen to Rihanna. Now, Gregg Anderson can add his name to that list.

Anderson, a postal worker from Grand Forks, B.C., was given the once-in-a-lifetime opportunity to sing alongside the former Beatle Thursday evening during the sound check for his Brooklyn concert.

"I'm feeling amazing," he told CTV News, still buzzing in his hotel room the next day. "Just overwhelmed."

The unforgettable night began with a simple act of charity. Anderson donated $50 to a campaign by Omaze, which raises money for worthy causes by offering tantalizing prizes, like a cameo role in Star Wars.

The latest offering: a chance to join McCartney at the mic for a duet of "Get Back."

Anderson was floored to find out he won on Monday, and just a few days later he was face-to-face with his idol on stage at the Barclays Center.

Though Anderson was a bundle of nerves at first, he said Sir Paul's demeanour quickly put him at ease.

"He made me feel very comfortable. Within 30 seconds all the nervousness and awe was gone," he told CTV News.

After some pleasantries, the legendary rocker was ready to play. "You know the words?" McCartney asked.

Anderson does know the words. He even knows how to do a pretty good impression.

"I did a little Paul McCartney vocal thing at one point," he said, laughing. "He looked at me and went, oh yeah!"

Once they were done, McCartney thanked Anderson for his donation to the David Lynch Foundation. Anderson thanked him back.

The lifelong fan said the experience meant the world to him, particularly because it came in the middle of a difficult time in his life.

"I lost my dad a few months ago," Anderson said. "It's been a crappy year and this has really made it better. And I'm pretty sure dad has something to do with it. He's up there laughing and smiling with us now."

Before Anderson left the stage, McCartney brought him in for a hug. He even let him hold his iconic Hofner bass guitar.

"My whole world was just spinning," Anderson said. "Just pure joy."

With files from CTV Vancouver's David Molko