I was rooting for her to lip sync it instead of singing it (by far the worse of the two options). I was praying for it. It's what kept me watching the clip.
He once did a show where he pretended that they were showing a rerun from 3 years ago. The rerun was going to be done live and with different guests playing the people who had been on when it originally aired.
It's like Craig Ferguson has mastered ancient and powerful Scottish magics. That's the only explanation for how I could like something with Rosie O'Donnell in it.