CINCINNATI, Ohio (WCMH) — Fiona, the world’s most internet-famous hippo, is about to become a big sister.

The Cincinnati Zoo and Botanical Garden announced Sunday in a social media post that Fiona’s mother, Bibi, is “doing well and on 24-hour birth watch.”

On Monday, the zoo shared a picture of Fiona with the caption, “Waiting to become a sibling is hard.” Also, a video of Bibi was posted noting that the pregnant hippo is “giving us a good look at her baby bump!” and teased the birth stating, “Could be any day now!”

Bibi’s pregnancy was revealed in April in a news release from the zoo, which touched on the concerns zookeepers had in light of Fiona’s struggles as a calf.

“The hippo team is excited and also nervous,” said Eric Byrd, manager of Cincinnati Zoo’s Africa team. “As most people know, Bibi’s first baby, Fiona, was born six weeks premature and wouldn’t have survived without the intervention of her human caregivers. We are hoping for a full-term pregnancy and will be doing everything we can to support Bibi.”

Some steps that were taken to ensure Bibi’s pregnancy was healthy included giving her hormone supplements and “performing regular ultrasounds to monitor the growth and health of the fetus,” according to the zoo.

Bibi was recommended to breed with a male hippo named Tucker who arrived at the zoo in September 2021, but her pregnancy came as a surprise.

“We weren’t planning to welcome a baby this soon, but nature found a way and ignored our calendar,” said Cincinnati Zoo’s director of animal care, Christina Gorsuch. “Most forms of contraception, in hippos or humans, is not 100% reliable. The dose that was previously effective for Bibi did not prevent pregnancy this time.”