Diana Ross got lit at a Hollywood eatery — without drinking a drop of booze!

The sizzling singer was having dinner with three male pals at the ultrahot bistro Dolce — owned by Ashton Kutcher and some “That ’70s Show” cronies — when a candle set her hair ablaze.

After recent stints in rehab, Diana was in a booth eating and sipping Voss bottled water, a fellow diner told The ENQUIRER. When one of her companions cracked a joke, the songbird tossed her head back in laughter — and her famous mane brushed against a lighted candle adorning the wall behind her.

“She was on fire,” the witness said.

A quick-thinking companion smothered the flame so quickly that few in the fancy restaurant were aware that the former Supreme was nearly sauteed alive.

Once the fire was out, Diana made a quick visit to the ladies’ room to make sure she still looked dazzling, then nonchalantly returned to her dinner.

“She acted as if nothing had happened,” the onlooker said.