Talk show titan The Big O "has fallen off the wagon" – admits shoveling chow constantly into gaping maw.

In a Harpo-360 move she made the not-so-startling confession in latest ish of vanity mag O and will discuss her corpulence on gal pal Gayle King’s radio show tonight.

"I’m mad at myself," Oprah wrote about hitting the dread 200 mark – again.  The chatty fatty’s weight has yo-yoed over the years – from a  liquid diet to her detox diet of doom in which she swore off meat and carbs – all to no avail.

Oprah, 54, blames her obesity on an out of balance thyroid gland and her "fear of working out".

Oprah hit rock bottom when she " was so frustrated I started eating whatever I wanted.

"I felt like a fat cow," Winfrey, a food addict, says. "I wanted to disappear."

According to the Center for Disease Control, Oprah’s weight body index is 31.8  "obese" and her health is at risk from "chronic conditions such as high blood pressure, diabetes and high cholesterol."

Diet tip for O – free of charge.  Keep your big mouth shut.