Kanye West unveiled a brand new track titled "Only One" featuring Paul McCartney on New Year's Eve. How did the two icons from completely different genres come together?

According to a statement from West's spokesperson (via Rolling Stone), the duo started working early last year in a small bungalow in Los Angeles. Their collaboration began with "a simple brainstorming session between the two, with McCartney improvising on the keyboards and Kanye vocally sketching and shaping ideas in a stream-of-consciousness riff."

The soft ballad is inspired by the Chicago emcee's baby daughter North, who was sitting on his lap when he was recording his auto-tuned vocals. He was singing, "Hello, my only one" -- the same words that his mom used to sing to him as a child.

"He understood in that moment that his late mother Dr. Donda West, who was also his mentor, confidant and best friends, had spoken through him that day," his rep said.

"My mom was singing to me -- and through me to my daughter," Yeezy also claimed, noting that his first name means "only one."

According to Def Jam, "Only One" is the first "publicly available recording from what has become a prolific musical collaboration between these two legendary artists" and "one of the most powerful and unexpected music collaborations in modern history."

And one thing for sure, the "Yeezus" rapper's wife Kim Kardashian digs the simple song, as she tweeted:

Kanye West's "Only One" featuring Paul McCartney can be streamed on his website and is available on iTunes.