The engaged couple Nick Kelble and Hayley Roll takes a shot with Baby Fiona at the Cincinnati Zoo and Botanical Garden. Image: Instagram/@hayley_roll

Hayley Roll will certainly remember how her fiancé Nick Kelble proposed. The moment even included an unexpected witness.

Kelble popped the question to Roll on Oct. 9 while visiting at their favorite hang-out: the Cincinnati Zoo and Botanical Garden in Ohio. The zoo is famous for housing a 10-month-old hippopotamus named Fiona. Since they were big fans of the hippo, they paid her a visit for the first time.

While kneeling down on one knee, someone took shots of the moment, while the baby hippo looked on the couple. The photos, uploaded on Roll’s and Kelble’s Instagram accounts, went viral weeks after the shots surfaced on social media.

“We’re so happy Fiona could be there on our special day. [H]ere’s to many more years of going to zoos with you,” Roll captioned her Instagram post.

We’re so happy Fiona could be there on our special day ❤ here’s to many more years of going to zoos with you 😙 @cincinnatizoo #cincinnatizoo #fionathehippo #fionafix #keepingupwiththekelbles #cincyzoopic

A post shared by Hayley Roll (@hayley_roll) on Oct 8, 2017 at 10:41am PDT

In an interview with The Daily Buzz, the radiology technologist Roll said that Kelble chose the day of their first anniversary to ask the question which would change both of their lives forever.

“[M]y boyfriend and I were waiting in line to get our photo taken with Fiona and I gave my cell phone to someone to take the photo and when I turned back around, Nick was on one knee proposing,” Roll said. They plan to marry next year, just in time Kelble graduates from college at the University of Cincinnati.

Here is a video of Fiona during her first time to get wet:

Fiona has been capturing hearts in the zoo and on social media since she entered the world prematurely on Jan. 24. Zoo officials thought she had slim chances of living, but the hippo eventually survived. Katrina Hallare/JB