How Can I tell the difference between these two 'Love is in the air' versions?

You can get the difference in youtube itself.

@ghanfer that’s the problem. they both look so similar that i can’t tell the difference.
i’m just suspecting that the youtube users don’t know as well. maybe it got all mixed up

do you know the difference?

Here is the Cat Stevens’ version.

Here is the John Paul Young version.

They do have a similar sound to their voices. Cat Stevens’ voice is a little rougher and more growly. They are also very similar arrangements. But the piano sounds different in the beginning.