Sir Elton John has recently revealed that is concerned about his friend, Lady Gaga.
"I look at Gaga and I think, 'How does she do it,'" said the 65-year-old singer speaking to the U.K.'s The Guardian.
The "Tiny Dancer" singer and Gaga, 26, have been friends for several years, and she is the godmother to John's young son Zachary.
Additionally, the British singer admitted that Gaga's parents harbor concerns about whether their daughter takes care of herself while on world tours.
"I talk to her mum and dad about it," he said. "They worry."
"She is frail," John continued. "And she doesn't eat when she should do, and she's a girl, and it's tougher for a girl."
Gaga, who has over 25 million followers on Twitter, remains one of today's most popular artists. Her demanding career and ever-diminishing weight has loved ones worried.
"She works really hard," added John. "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."
Meanwhile, John's health saw a recent downturn. The singer was forced to cancel a show in Las Vegas after being hospitalized for a serious respiratory infection last month.
"All I can say to fans is sorry I can't be with you," the singer said in a statement at the time. "I hope to see you soon at this wonderful theatre of Caesar's Palace."
Fortunately, today he is doing "incredibly well," according to The Guardian.
John recently teamed up with stars such as Paul McCartney to honor Queen Elizabeth II during her Diamond Jubilee this week. The singer, who has performed for the Royal Family many times in the past, conducted sing-along versions of "I'm Still Standing," "Your Song," and "Crocodile Rock."
Gary Barlow, Tom Jones, and Annie Lennox, among others, also performed during the event, which also saw a massive fireworks display over Buckingham Palace.
Although her husband, Prince Phillip, was unable to attend the Gala Concert Monday due to illness, the Queen watched the performances from the Royal Box alongside Prince William, Kate Middleton, and other Royal Family members.