SPAGO BOOM! Busted Skylight Panel Drops Glass On Lunch

5/1/2013 3:00 PM PDT

Waiter! There's a chunk of glass skylight panel in my soup!

We joke because no one got hurt ... but this is SCARY ... a glass skylight panel at Spago just crumbled and dropped glass in the main dining room during lunch service.

The room was cleared -- customers were moved out to the patio -- and repairs are already under way.

A restaurant spy tells TMZ ... the panel merely cracked and crumbled ... but the safety netting inside held most of it together ... only small bits of glass rained down. Again -- so far NO reports of anyone getting hit.

The panels (stock image from Spago's website above) are about the size of your average small apartment window ... and are fairly new ... they were part of the renovations before the hotspot's reopening last September.

And they say there's no breaking through Hollywood's glass ceiling.