Ayda, 37, appeared on U.K. TV show Loose Women on Monday (31Oct16) and revealed the Angels hitmaker, now 42, has never gotten over being labelled 'fat' when he was a teenager.
"He was called fat when he was 15 in Take That, which I think is disgusting," she said. "He has been on a diet ever since."
Taunts at the time included the nickname 'Blobbie Williams' and clearly, the hurtful comments have affected his self-esteem ever since.
"He always says no to pie at birthdays and Christmas," the American actress added. "My man should be allowed to have pie!"
Austenland star Ayda also revealed her husband is terrified of failure.
"He works so hard and loves his fans so much," she explained. "He wrote 65 songs for his latest album and never wants to let anyone down. He is a working class man."
And despite her man's confident public persona, Ayda says he is riddled with inner fears and insecurities.
The father of two made his own revelations recently, admitting he has had some cosmetic procedures and a little surgery to improve his looks.
"I've had some fillers and some Botox, and I've had something done to my chin, which means I can't even move my f**king forehead," he laughed at the Attitude Awards in London on 10 October (16).
Certainly, his healthy eating habits, and the fact that he has given up smoking, seem to be paying off. Last week (ends28Oct16), Robbie was spotted filming a video on a remote beach in Kent, reportedly for his Christmas single. Surrounded by beautiful women wearing bobble hats, black jackets and leggings, the former heartthrob looked extremely slim and healthy in a tweed coat.