Kim Kardashian and Kanye West Go Back 8 Years

According to our sources, the two have been friends since 2004 -- and have flirted on-and-off -- but the timing was never right to pursue a relationship ... until now.

We're told both sides always felt a spark, but they NEVER acted inappropriately while Kanye was with Amber Rose ... or while Kim was with Kris Humphries.

In fact, we're told Kim was recently kicking around the idea of reconciling with Reggie Bush ... but after hanging out with him in Miami a few weeks ago, decided the two weren't compatible anymore.

Kim finally reconnected with Kanye in Paris when she attended his fashion show ... and shortly after that, both sides decided to "give dating a shot."

And so far, we're told Kim has been super-impressed with the rapper ... who pulled one hell of a surprise when they hit up FAO Schwarz in NYC a few days ago.

Sources say Kanye made some calls and had an entire floor of the toy store roped off so they could get a private lesson from a guy who taught them how to play "Chopsticks" on the over-sized piano featured in the movie "Big."