Jett Travolta, 16, died on Friday morning after suffering a suspected seizure at the family holiday home in the Bahamas.
Jett was the most wonderful son that two parents could ever ask for and lit up the lives of everyone he encountered,' reads a statement from John, 54, and Kelly, 46.
'We are heartbroken that our time with him was so brief. We will cherish the time we had with him for the rest of our lives.'
A local police source said Jett, who had a history of seizures, hit his head on the bath.
An autopsy is due to be carried out today.
John and Kelly are also parents to 8-year-old daughter Ella.