I heard this joke a long time ago, and it was brought to mind again by the great news:
A guy walks into the doctor office and says: "You got to help me doc, I've been walking around for weeks now singing the same song. I can't get it out of my head...I just keep singing the 'The Green, Green Grass of Home'; what's wrong with me."
The doctor pokes around a bit, then sits down to think for a few minutes, and finally says: "Well, I think there's a good chance you have 'Tom Jones Disease'."
The guy says: "Tom Jones Disease? I've never heard of that, is it very common?"
The doctor thinks for a moment, then say: "Well, it's not unusual."
Bah Dum Dum!
Speaking of Tom Jones jokes, check out this...if you like wasting your time.