Kevin Durant and LeBron James are rivals on the court, currently competing against each other for the Larry O'Brien trophy, but we all know they're good friends off the court. What we didn't know, or expect, is that the two have been sitting on an unreleased song that they collaborated on six years ago.

ESPN's Chris Haynes has reported that Kevin Durant and LeBron James once collaborated together on a hip-hop track back in 2011 during the NBA lockout.

“I heard the track years ago during post production for ‘Thunderstruck,’” said agent Eric Goodwin, who executive produced the film and once represented both Durant and James. “It was very good. I suggested submitting it to Warner Brothers for the movie soundtrack, but KD wanted to keep it private.”

According to the report, one person who has heard the song says Durant handles the opening verse while LeBron comes in for the second, followed by another KD verse to close things out.

Unfortunately, it's unclear exactly what the song is about or where it is being stashed, though it is believed that Durant provided the instrumentals for the track.

Haynes writes,

"When approached about its existence, James and Durant, to a moderate extent, confirmed that there is such a track before bursting out into laughter without further comment."