This happened Friday night at the Hollywood Bowl. My friend George just told me about it. I guess it's going viral. A voice teacher was in the audience at a Kristen Chenowith concert when she volunteered to come up on stage and sing a duet with Kristen. It's a part of the show that they ask for a volunteer to sing with Kristen but she's not a plant.
Now I don't know Kristen at all (except I do seem to recall seeing her on an awards show where I thought she was funny and talented). That being said, I love her now and am a huge fan, as I am of this woman, Sarah Horn.