Antony Costa and wife-to-be Rosanna Jasmin had gone to an open evening at the hotel where they are planning to get married - and took their little girl Savannah along with them.
But, as they began tasting wedding cakes at the Cambridgeshire venue, Rosanna quickly noticed that something was horribly wrong.
Speaking with The Mirror, 33-year-old Antony explained: "[Rosanna] noticed Savannah’s head had tilted and her eyes were rolling back.
"In a second, she started shaking and going stiff in Rosanna’s arms. Then her lips turned blue.
"We didn’t know what was happening. We really thought she was dying."
The fit lasted an agonising 10 minutes - but, thankfully, Rosanna had recently seen a film on first aid for infants.
She quickly laid her little girl down and tilted her head, to stop her from choking.
But, when she moved in to do mouth-to-mouth resuscitation, a woman quickly rushed over to stop her,
Antony said: "It turned out she was a doctor. She told us not to do mouth-to-mouth because Savannah was still breathing.
"It sounds obvious now, but when you’re there in the moment it’s very different."
Savannah was quickly rushed to hospital, where doctors revealed she had a virus which had caused her temperature to increase, throwing her into a fit called a 'febrile convulsion'.
Antony said: "They couldn’t tell us if it would happen to Savannah again. But they said it can happen to anyone – children can suffer from them up to the age of five.
"We are definitely going to go on a baby first aid course now. We don’t ever want to be in that position again.
"When you have a baby, you are taught how to feed it, how to change a nappy and things like that, but they don’t teach you what to do in an emergency like this.
He added firmly: "I wanted to talk about this because I think every parent should go on a first aid course, so everyone knows what to do if they are faced with an emergency."
We're so glad to hear that Savannah is ok - and we are glad that Antony Costa is using this opportunity to encourage other parents to take baby first aid courses.
TO FIND OUT MORE ABOUT BABY FIRST AID COURSES IN YOUR AREA, VISIT THE BRITISH RED CROSS WEBSITE NOW.