Modern Family Star To The Rescue

The "Modern Family" star was leaving Hyde nightclub at the Bellagio around 3 AM on New Year's Day ... when Sofia saw a woman hit the deck.

Sources at the scene tell us ... Sofia and a girlfriend rushed over to the woman to help. We're told Sofia's friend had medical training and was seen checking the woman's pulse.

Both Sofia and her friend tried to keep the woman calm ... and waited by her side until security personnel and paramedics arrived to the scene. We're told the woman was eventually transported to a nearby hospital.