John Travolta thinks of his late son every day

Sharing a throwback photo of himself with Jett in Kelly's arms, he wrote: "Happy birthday my Jetty - not a day goes by where you're not with me!"

John and Kelly's daughter Ella Bleu, 24, commented on the post: "Happy Birthday Jetty [five heart emojis] (sic)"

And family friend Risa Wilson posted: "Will never forget him. Or Kelly [double heart emoji] (sic)"

Ella later shared her own throwback photo of herself and her brother and wrote: "Happy Birthday, Jetty. I love you always [heart emoji] (sic)"

John previously revealed how his own views on mortality changed after a profound conversation with his son Benjamin, now 13, after Kelly's death, which came two years after she was diagnosed with breast cancer.

Retelling their heart to heart to Kevin Hart on his Peacock talk show 'Hart to Heart', he began: "[Ben] said to me once, 'Because mom passed away, I'm afraid you're going to.'

"I said, 'Well, it's a very different thing.' And I went through the differences about my longevity and her limited life.

"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.'"

Ben then asked his dad if he sees himself still being alive in three decades' time and admitted that by the end of their conversation his whole "viewpoint" on getting older changed.

The 'Pulp Fiction' actor continued: "I said, 'Yeah.' He said, 'Does 30 years ago seem like a long time?' I said, 'Yeah.' He said, 'Don't you think you have 30 more years in your life to live?' I said, 'Yeah, I do. I have at least 30 more years.' He said, 'What's wrong with that?' This is a 10-year-old telling me that! It changed my viewpoint."