In view of her 1.5 million Instagram followers, Gemma explained that her dad never “recovered” after he too suffered cardiac arrest.
The 35-year-old admitted her life “changed forever” following the sudden tragedy.
In the caption of the video, originally posted by the British Heart Foundation, Gemma wrote: “This is what happened to my dad when I was 17, only he didn’t recover.
“He passed away and our lives changed forever.”
“CPR should be taught in schools, so that hopefully you don’t ever have to use it, but if you do, you know exactly what to do and it’s just an automatic reaction,” another social media user commented.
A third person added: “That’s terrible to hear. So sorry. Thank you for using your experience to help others.”
While a fourth person wrote: “Great charity to be working with. They do great work.”
The former Emmerdale has previously opened up about the loss of her dad on the picture-sharing site.