Kelly Preston has paid a touching tribute to her late son.

Kelly, Jett and John (c) Instagram

Kelly, Jett and John (c) Instagram

The 56-year-old actress marked Autism Awareness Month by sharing a photo of Jett, who died aged 16 in 2009 after suffering a seizure, being kissed by her and her husband John Travolta and pledged the youngster would be in her heart "forever".

She captioned the Instagram post: "To my sweet love, Jett... you are in our hearts forever.

"I send love to all of the beautiful autistic children and the wonderful people who love them. May we all shine and grant love and respect to children with special needs [heart emoji] #autismawareness #autism (sic)"

John, 65, added a heart emoji in the comment section of the post.

The 'Saturday Night Fever' actor - who also has Ella, 19, and eight-year-old Benjamin with his wife - previously opened up about how his youngest son's birth brought their family together, five years after Jett's passing.

He said: "We certainly have bonded together.

"Certainly having little Ben has been a beautiful kind of glue for us to rebond after a tremendous loss."

And the 'Pulp Fiction' actor is thrilled that his son Benjamin is interested in following his parents into the film industry but insisted he wouldn't "force" him.

He previously said: "I took him to Toys 'R Us recently, and he said to me when we got out of the truck and in the cart, 'Why are all these people wanting my photograph?'

"Because I didn't know if he knew I was in films or not. He said, 'Well, maybe they saw one of your movies!' And he said, 'I want to work with you!' So we'll see how that evolves. I don't want to force it."