We've never seen her so happy!
James Corden has been totally nailing his new role as the host of the The Late Late Show, but the British star faced his toughest diva test yet when Mariah Carey showed up on the scene for his Thursday night show.
But ol' Jimmy C totally seemed in command as he drove Mariah around in his car before imposing a little music magic on the scene.
He "accidentally" put on a few of Mariah's greatest hits, and suddenly an impromptu karaoke session was in play!
And you know what?
These two make one wonderful team! And James Corden really knows how to push the right Mariah buttons as she seemed to be having the time of her life!
Check out EXACTLY what we mean by watching the video (below) !!!