In 1984, Paul McCartney did a movie called "Give My Regards to Broad Street", which was basically about a fictional day in his life.

The movie bombed, but it did have a cool scene where Paul performed with a guitar on a London street corner, and no one recognized him.

Apparently, the scene was LEGIT.  They actually put Paul on the street, and the people he was performing to were NOT actors.

Of course, he wasn't trying to look like, or even sound like, himself. His hair was ruffled, and his clothes were disheveled.  He was performing "Yesterday", but it was a different, folk version of it.

In an interview at the time, Paul said, quote, "[The producers] just made me up and dropped me off.  I told 'em we'd never get away with it, but they kept putting dirt on and rufflin' up my hair and I figured, why not?

"So, I was standin' there plunkin' chords, doing this silly version of the song, and no one noticed it was they'd toss coins and I'd be going, 'Yesterday, all my troubles...thank you, sir... seemed so far away.'"

Paul didn't keep the money he got.  He donated it to a local mission.