People do collaborations all the time on You Tube.
I was asked to provide the vocal for a tribute video to John Lennon.
I had some minor but annoying challenges with this little project, the video I was to send, had to have me singing acapella, I could only use the little mic on my tiny video camera to record my voice, and of course, it all had to be done in one take. The key of the song was very awkward, too high for me to belt it out comfortably, and too low to be really dynamic at the high points, but the track was done by the time they got me on board so there was no changing the key.
After trying a number of things however, I just sat down and sang the song simply, after all, there is no point messing with John.
Lai decided to put some harmonies over my vocal, which he says he has never done before so that must have been cool for him. I am very glad I decided to play along with this, Lai has about 3 thousand subscribers to his You Tube channel, and I woke up this morning to an inbox full of subscribers and new friend requests who found me via his video, and the requests still keep coming.
I do show up in this video, for the last verse and chorus.