The 43-year-old radio host informed listeners that her friend and KIIS FM Content Director Derek 'DB' Bargwanna had recently lost his son Tate who "died peacefully in his sleep".
The whole team at KIIS was deeply affected by the news with Jackie confirming they are like a "family" and that staff members had attended Tate's funeral on Saturday.
Jackie O revealed, "[DB's] four-year-old son Tate died in his sleep and it was completely unexpected and we don't know why."
"He died peacefully in his sleep. And it has hit us all really hard and we've tried every day to go on air and carry on because DB would never want us to take a day off."
"But it has been really traumatic for the whole team and we want to send our love to DB and his beautiful wife Belinda,"
"They have two other beautiful children, Beau and Colby."
The tragedy hit close to home for the KIIS FM team, with Jackie saying, "We've done a lot of givebacks on this show and we've met people who have gone through similar things."
"At the time, when you meet these families, you have an enormous empathy for what they're going through. But it's not until it happens to someone you know and love dearly that you realise just how difficult that grief is and how it changes a family."
"And to see that happen to someone we know and love so much has been really hard,"
"I hope no-one out there ever has to go to a child's funeral because it was one of the most unfair things you could go through."
She concluded the segment with well wishes to the family and that she hopes they can now begin the "healing process" following the tragedy.