The son of Travolta and late actress Kelly Preston - who died in 2020 at the age of 57 after a long battle with breast cancer - had experienced seizures multiple times throughout his life and was hospitalised for 15 months with lymph node syndrome Kawasaki disease as a young child.
Travolta - who is also father to Benjamin, 11, and Ella, 22, with Kelly - was inundated with comments on his post as he remembered his late son
Actress Jamie Lee Curtis wrote: "Oh John. My hand in yours. X j", while John's daughter Ella wrote: "Happy Birthday Jetty, we love you so much" and actress Emma Booth also sent a birthday tribute.
Back in November, John opened up about how he explained his family tragedies to Ben - who was born just 18 months after his brother's tragic death - and told him that all he had to do was "trying to live the longest" he can because "no one knows when they're gonna go".
He said: "I said, 'But you know, Ben ... you always love the truth and I'm going to tell you the truth about life. Nobody knows when they're gonna go or when they're going to stay. Your brother [Jett] left at 16. Too young. Your mother left at 57. That was too young. But who's to say? I could die tomorrow. You could. Anybody can. So let's look at it like it's part of life. You don't know exactly. You just do your best at trying to live the longest you can.'"
