TMZ has learned ... Zsa Zsa Gabor is being rushed back to UCLA Medical Center.
Zsa Zsa's husband, Prince Frederic von Anhalt, tells TMZ, "I just called an ambulance. She has to go back to UCLA."
The Prince says the 93-year-old Zsa Zsa was unresponsive and clearly in distress.
An ambulance is on the scene after 911 was called.
No word yet on the nature of the emergency.