"From the time that song comes on, I was sold completely," Luke says in a promotional video. "At that point it's up to me to find out who's going to be the girl voice. � I had thought about individual female artists and I wasn't thinking about a girl in a group.

"Finally, I saw Karen one day and the light bulb went off and I told her and sent her 'Home Alone Tonight' and she liked the song � I feel like it's something that's going to take me to another level as an artist. I hope she's that excited about it. I think she is."