Brad Keselowski has shared a touching personal story about the late Greg Biffle, who died in a plane crash in North Carolina on Thursday.

Biffle and six others, including his wife and two children, tragically lost their lives in the accident, the cause of which is still being investigated by authorities.

A flood of tributes poured in from around the NASCAR world, but Keselowski's was a little delayed – and as it turns out, for good reason as he was going into surgery for a broken leg at the time of the crash.

The RFK driver and co-owner took to social media on Friday to share his story, admitting he was 'not really sure' of what to say to such a huge loss.

Keselowski: This is my favorite Greg story

In his post, he wrote: "I broke my leg and was going into surgery when the tragic plane accident happened to Greg and his family. Not really sure the words to say so I’ll share a story:

"I called Greg a few years ago telling him my friend really needed a fun trip after losing a family member, could we all go ride his UTV’s together to show my friend a good time?

"Without missing a beat he made all the plans & we had a great sand dunes trip, my friend was all smiles. This trip means so much more now… this is my favorite Greg story, Will miss you and your family. #GodSpeed"

Keselowski's story is just one of dozens which have been told about the 55-year-old Truck and Busch Series champion, as tributes continue to flood in to him and the others who lost their lives this week.

NASCAR TODAY: Greg Biffle death sparks emotional outpouring among sport's community