Beth and Jamie Wilson had already travelled an emotional IVF journey to have their first child, and were preparing to head back to the clinic to start trying for baby number two.
So when Beth realised she was pregnant and had conceived naturally, she couldn't wait to share the exciting news with her husband.
A video of the moment the mum broke the news to an unsuspecting Jamie shows he was just as surprised as his wife about the happy news.
The clip, which the mum secretly taped while pretending to take a selfie, shows Jamie opening which he thinks is a handmade gift from two-year-old son Eli.
But instead he finds a positive pregnancy test wrapped in a baby blanket inside the gift box labelled "Daddy".
"What's this... what does that mean? What? I'm confused," the 37-year-old says. "What? What the f***?"
He then realises the good news Beth, 34, is trying to tell him. "Are you kidding me?!" he says.
The couple, from the UK, began trying for a baby in 2006 and underwent four failed IVF attempts before a successful round resulted in the birth of Eli in 2014.
They were just about to start an expensive round of IVF and, because they already have a child, the couple does not qualify for financial help in the UK.
Beth and Jamie already had four frozen embryos but were facing a bill of almost $3000 for the implantation to be carried out.
Jamie told Daily Mail that the possibility Beth was pregnant was the last thing on his mind when he opened the box.
"I thought maybe Eli had made me something, and my thoughts were on everything else - apart from Beth being pregnant," he said.
"The penny started to drop when I saw the test, but I was still questioning myself."
Beth is now 22 weeks pregnant and their second son is due to arrive on June 16.