Every now and then a country star will join up with someone completely unexpected and the collaboration can often result in something pretty good.

Willie Nelson recently took the stage in Austin, Texas and had a guest guitarist with him. The mystery guest was simply introduced as 'John.' Most people in the crowd didn't even realize they were seeing actor Johnny Depp playing alongside the country legend. Take a look at the video. Johnny is the one wearing the fedora.

In 2003, Tim McGraw teamed up with Sir Elton John at the AMA's to do an excellent rendition of Elton's 'Tiny Dancer.'

Maybe the most unexpected live collaboration though came in 2013 at Kensington Palace when Taylor Swift and Jon Bon Jovi were joined on stage by Prince William. The three of them sang together on Bon Jovi's hit song 'Livin On A Prayer.'

Are there any other collaborations you can think of that you found unexpected and cool?