After blowing up to her highest weight ever at 280 pounds, OPRAH WINFREY has been told to diet – or die!

The 57-year-old media mogul had been binge-eating and booz­ing due to stress over her failing network, her stagnant love life and the betrayal of her best friend Gayle King, who jumped to anoth­er network, say sources.

And the extra bulk has put her in extreme danger, according to medical ex­perts.

Shocked to see how big she’dgotten in photos, Oprah finally went on a strict low-calorie diet and power-walking routine in a desperate bid to slim down, add the sources.

“Hitting the 280-pound mark has opened Oprah up to a world of life-threatening health troubles – everything from diabetes to heart problems,” divulged a close source.

“She’s been told by people in the medical field that this time, it’s diet – or die.

“Friends and loved ones have impressed upon Oprah that this is her final warning as far as her weight is concerned and urged her to start a new diet and exercise program.

“They’re seri­ous and, thankfully, she’s listening.”

Over the past 25 years Oprah’s weight as yoyo-ed wildly from a svelte 130 pounds in 1988 to her dangerous obese condition.

Oprah finally got a wakeup call after receiving the Jen Hersholdt  Humanitarian Award at an Oscar event November 12th.

To her horror, pictures showed her spilling out of a shapeless, tent-like dress, said a source.

“Oprah was humiliated when she saw how fat she looked,” the source revealed. “After that she cut the boozing and the feeding frenzy. She switched to drinking water, eating fruits and vegetables and even power walking daily.”

Oprah has given up many of her favorite foods including pizza, double crust chicken pot pie, caramel corn ice cream, sour cream pound cake and bacon-peanut truffles.

“She knows the sacrifice is saving her life right now,” added the source.