If you loved Kristen Bell singing "Do You Want to Build a Snowman?" live, you're in for another treat. During the same performance at LA's Vibrato Grill Jazz Restaurant, Bell was joined by Santino Fontana, the voice of her animated Frozen fiancé, Hans, for a rendition of "Love Is an Open Door." It's mind-blowing how good they are live. Check it out, and try not to get this catchy love song stuck in your head for all eternity.