George Clooney says Presley Gerber's death is "one of the most devastating things that's happened to our family".

The 65-year-old actor and director has been close friends with Presley's parents, Cindy Crawford and Rande Gerber, for years and admitted the death of the 27-year-old model last month has hit them all hard.

Speaking to Entertainment Tonight at The Albies in London, Clooney said: "Quite honestly, it's one of the most devastating things that's happened to our family,. And their family is just as you can imagine.

"It's the worst thing that could ever happen with family."

Presley - the son of supermodel Cindy, 60, and businessman Rande Gerber, 64 and brother of model/actress Kaia Gerber, 25 - died at a rehabilitation facility in Santa Monica on September 20.

His remains have already been cremated at the Rose Family Funeral Home in California and the family is planning a "small" and "private" service of remembrance.

A source told PEOPLE: "They're still deciding...

"It's hard to make those decisions when everyone is struggling emotionally. Their priority is to keep it private, without media or paparazzi there."

A second source added: "[They are] still figuring out what to do in terms of a memorial.

"They want to keep it very intimate, but there's so many people in Presley's life who loved him, the amount of people that have reached out to attend is high.

"The plan right now is somewhere in Malibu because of his love for surfing and the beach."

Presley - who had spoken publicly about his struggles with addiction and mental health - was found dead at a luxurious rehab clinic and his official cause of death is still pending investigation.

Speaking previously about Presley's death, the Santa Monica Police Department said officers were called to the 1000 block of Berkeley Street at about 9:35am on Sunday 20th September, following a report of a possible overdose.

Police said: "Upon arrival, officers located an adult male who was deceased."

The department added: "SMPD detectives are investigating the death as a suspected overdose. At this time, there is no indication of foul play. The investigation remains ongoing."

The Los Angeles County Department of Medical Examiner said Presley was pronounced dead by responding paramedics at 9:45am. An examination has been completed, but officials have deferred a ruling on both the cause and manner of his death while additional testing or studies are carried out.

The medical examiner said deferred cases can take several months to determine.