Fans went crazy Monday night at New York's legendary Ed Sullivan Theater when country icon Willie Nelson made a surprise appearance with Snoop Dogg during the rapper's 'Live on Letterman' performance. Willie talked of their time together in Amsterdam before the duo sang 'Superman,' a track Willie wrote for Snoop's last album.

Johnny Cash. Watch them in the 'My Medicine' video
here, and stay tuned to The Boot for exclusive video from their 'Live on Letterman' performance, which we'll have later this week.

Matt Simpson