The man known as Pedro, from Portugal, was filmed as he was handed a pair of EnChroma glasses, which enhance colour perception.
His wife, Ana Paula, then handed him a series of cards with messages on that were written in colour to see if he could read them.
The last flashcard Pedro read was the most important one.
It read: “Last one daddy, what’s on mummy’s T-shirt?”
Pedro looked over to his wife to see her shirt that read: “It’s a girl” in pink and green lettering.
“I’m not going to start crying,” the dad-to-be said to the camera as he scooped his wife up in his arms.
”At least he managed to read the shirt,” Paula said through tears.