Bob and Mark performed 'Forever Young' Monday night when they wrapped up their European tour in London. Check out the video.

It's not very often that Bob Dylan lets someone join him on stage, but for some reason in the past few weeks he has let Mark Knopfler (former Dire Straits frontman) in on his gigs.  But until Monday night Mark was only allowed to sit in with the band, then when it came time for the last song Bob invited Mark to join him to sing 'Forever Young'.