He admits he worries about the "frail" 26-year-old pop star, who is godmother to his son Zachary, as she travels for her Born This Way Ball tour.u00a0"I look at Gaga and I think, 'How does she do it?' I talk to her mum and dad about it. They worry.

"She is frail, and she doesn't eat when she should do, and she's a girl, and it's tougher for a girl. She works really hard. She will be in Denmark one night and Saudi Arabia the next. I know how tiny she is and I do worry about her, yes," he added.u00a0