Cameron Boyce's sudden death at the age of 20 was caused by epilepsy, a coroner has confirmed.
The young actor appeared in horror film Mirrors, espionage thriller Eagle Eye and Adam Sandler comedy Grown Ups before becoming a Disney Channel favourite in the musical film Descendants and TV series Jessie.
He died after being found unconscious at his home in North Hollywood, Los Angeles, on 6 July.
His family had said he had suffered a seizure as a result of "an ongoing medical condition", for which he was receiving treatment.
Paying tribute at the time, they said in a statement to ABC News: "The world is now undoubtedly without one of its brightest lights, but his spirit will live on through the kindness and compassion of all who knew and loved him."
On Tuesday, the Los Angeles County department of medical examiner-coroner said Boyce's cause of death had been determined, calling it a "sudden unexpected death in epilepsy".
A post-mortem had been carried out on 8 July but further testing was needed. The actor's manner of death was "natural", the coroner said.
Following his death, Disney cancelled the premiere for Descendants 3, saying the TV broadcast would instead be dedicated to the young star's memory.
Away from acting, Boyce had also taken part in significant charity work, including raising more than $27,000 (£21,562) for the Thirst Project, which helps bring clean water to underdeveloped countries.
The Disney Channel said Boyce had "extraordinary artistic talents" and was "fuelled by a strong desire to make a difference in peoples' lives through his humanitarian work".
He played Luke Ross in Jessie, and Carlos in Descendants, the TV movie series.
Following his death, co-stars including Sandler, Dove Cameron, Salma Hayek and Debby Ryan were among those to pay tribute.
In a statement posted on social media, Sandler said: "Too young. Too sweet. Too funny. Just the nicest, most talented, and most decent kid around.
"Loved that kid. Cared so much about his family. Cared so much about the world. Thank you, Cameron, for all you gave to us. So much more was on the way. All our hearts are broken.
"Thinking of your amazing family and sending our deepest condolences."
© Sky News 2019