It's the version he sang over the weekend at the Maxim party. He sings Enrique's verse. He sings the chorus anyway.
The Spanish song he sang completely himself. It went #2 in Spain last year. I don't think anyone realised he sang it, and thought his feature credit was for production.
It's live. There's a backing track, but you can hear him clearly. Not bad. He sounds like Marc Anthony and Enrique put together.