Steve Cruickshank does some really interesting music projects on his YouTube channel. This one is part of a series he did mashing up various Elton John songs with John Lennon / Beatles songs, I assume just based on the fact they both have "John" in the name? I think this is my favorite one, it's Your Song/And Your Bird Can Sing.

His channel is more well-known for making "negative harmony" covers of songs which flip the harmony "upside down"; I think his negative harmony cover of "Don't Speak" by No Doubt is probably my favorite of those.