My first exposure to Steve Martin as a banjo player was at a Nitty Gritty Dirt Band concert at Carnegie Hall in (I think) 1975. He joined the band on stage, was introduced, and I thought, "That's the comedian guy; didn't know he could play." I decided he could play right well.
Now I've found this video of him playing "Crow," which he composed, with two of the greatest living banjo players. I first knew of Tony Trischka as part of Country Cooking, whose album 14 Bluegrass Instrumentals I acquired some thirty years or so ago. (I now have its CD successor, 26 Bluegrass Instrumentals.)
Here's Tony, backing up fiddler Tashina Clarridge (note her appreciative laughs at 3:08 and 3:14), along with guitarist Michael Daves and bassist Skip Ward (more about these two later), doing "Sally Goodin" at the 2011 Joe Val Bluegrass Festival in Framingham, Massachusetts.
I learned of Béla Fleck later. At first, I thought him a bit weird. As I developed more of an appreciation of jazz, which his style seemed to edge into, and saw the synergy between it and bluegrass, I came to like him very much.
"Big Country" has Béla playing with a decidedly non-bluegrass backing band, having some woodwinds, including a bassoon, as well as a keyboard and steel drums.
The fiddler on "Crow" is Brittany Haas. Here she is in duet with Lauren Rioux doing a medley of "Grey Owl" and "Red, White, Blue and Gold"; on the latter she shows her talent on the banjo and, along with Lauren, as a vocalist:
Guitar on "Crow" is by Michael Daves, who is in his eighth year of residency at our local Rockwood Music Hall. Here he is doing "Mule Skinner Blues" at the Rockwood in December of 2010:
The bassist on "Crow" is Skip Ward.
On "Crow." he plays acoustic bass. In the above clip of "Clean" by the Darren Lyons Group, he plays electric bass in a fusion piece, performed at B.B. King's Blues Club in 2011.