The Avett Brothers
The Avett Brothers is a critically acclaimed American band from Concord, North Carolina. The band is made up of two brothers, Scott Avett (banjo) and Seth Avett (guitar), as well as Bob Crawford (double bass) and Joe Kwon (cello). Mike Marsh (drums) and Paul Delfigia (keyboard) are touring members of the band, with Kwon featured on recordings from 2007's Emotionalism and later.
source: Wikipedia