Arianny Celeste -- the most famous UFC octagon girl ever -- has announced she's pregnant ... and will be stepping away from the cage for a bit.
34-year-old Celeste tells TMZ Sports ... she and her boyfriend Taylor King are expecting their first child in September.
Celeste says she hasn't been working UFC events recently due to the pregnancy -- and plans on taking some time off until after the baby is born. So, she won't make thew trip to Fight Island for UFC 251.
But don't worry, Celeste says after the kid is born she plans on returning to her job .