ROY, Utah – A Utah couple managed to keep a big secret from members of their own family for nearly nine months.

When Tannin and Katie Pease found out Katie was pregnant with their third child, they decided to wait as long as possible to tell Tannin’s mom. In fact, they managed to keep it a secret until the day before Katie was set to deliver, according to KUTV.

The family recorded the moment they revealed the news to Tannin’s mom, Carolynn.

So how’d they manage to hide the pregnancy for nearly nine months?

Well, it helped that Carolynn lives in Montana, but keeping the secret still involved a pretty large cover-up. Tannin explained the elaborate effort to KUTV.

Katie’s side of the family knew, but agreed to help keep it hush-hush.

Tannin said they came up with nine months worth of excuses and alibis to explain why Katie couldn’t attend events. They also changed the settings on their Facebook accounts so no one could tag Katie in a photo without their approval.

When they Skyped with Tannin’s mom, they made sure only Katie’s face could be seen. It had to be hard for the couple’s two young sons, but they managed not to give away the secret.

Eventually, Tannin’s dad came into town for a business trip, but he agreed to help keep the secret to surprise his wife. Finally, Tannin invited his mother to visit, saying they had a big surprise for her — and judging by her reaction, she was pretty blown away.

In the video, she’s almost too stunned to speak at first.

“Guess what? We’re going in to have the baby tomorrow,” Tannin tells his mom.

She throws a bag of croutons to the floor, leans on the banister and wipes tears from her eyes.

“How long have you known?” the stunned woman asks after seeing Katie’s baby bump.

“Oh, about nine months,” Tannin says.

The next day, the couple welcomed Saul Lane to the family.

“Mom and baby are home and happy!” Tannin wrote on Facebook. “Thank you to everyone who helped out over the last few days and those who helped with the secret!”