Lady Gaga is about to perform three stadium shows in Auckland, but Sir Elton John says she might not be taking care of herself on the road.
The music legend explained that the star - who is godmother to his son Zachary – was on his mind because she works extremely hard.
"I look at Gaga and I think, 'How does she do it?' he told The Guardian.
"She is frail, and she doesn't eat when she should, 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 also admitted that her parents are anxious about the 26-year-old singer’s health.
"I talk to her mum and dad about it. They worry."
Lady Gaga's first New Zealand show is at Auckland's Vector Arena on tonight.