And this is why she's superstar. Although she IS a superstar and she has people schedule in time for this.
According to one of the members of her opening act (from her UK tour), Stooshe, this is what Jennifer does:
"I love her. We were standing on the side of the stage the other day watching her and she's amazing. So inspirational. She works out just before she goes on stage for an hour in her hair and make-up and outfit. Then she literally just floats on stage. It's crazy."