If あなた were to have a duet with with your お気に入り singer, which song would the two of あなた sing?

I'd 愛 to do a duet with Idina Menzel! She's my お気に入り Broadway actress and singer, and one of the most inspirational women I've ever seen.
I'm a massive ファン of symphonic metal bands like Within Temptation, and I think her powerful voice would fit perfectly. I chose the song from above because it's already a duet.