Watch this video there are so many facts about this that I've gone from thinking its a load of bs too it's a possibility watch the link about faul McCartney who was the double for Paul and you'll find out a lot.
https://m.youtube.com/watch?feature=related&v=N4McYkNXFQY
https://m.youtube.com/watch?feature=related&v=N4McYkNXFQY