Essex Police said the man, who has not been named, was arrested “in connection with the indecent assault and murder of Stuart Lubbock”.
Mr Lubbock, 31, had been attending a party at Barrymore’s luxury home in Roydon with eight other people on March 31, 2001.
Barrymore was criticised for leaving his home soon after Mr Lubbock was found floating in the outside pool.
The 68-year-old former television presenter, who became a household name for shows such as Strike It Lucky, has always denied involvement in the death.
A post-mortem examination showed Mr Lubbock had suffered severe internal injuries which suggested he had been sexually assaulted.
Alcohol, ecstasy and cocaine were found in his bloodstream.
Barrymore was criticised for failing to answer questions at the inquest in 2002.
He also said he could not jump in and try to save Mr Lubbock because he could not swim, a claim disputed by others who knew the star.
The coroner recorded an open verdict.
Barrymore, his former partner Jonathan Kenny and fellow party guest Justin Merritt were arrested in 2007 on suspicion of sexual assault and murder, but were later released without charge.
Barrymore repeatedly denied any wrongdoing, last year saying: “I have had nothing to do with this whatsoever and yet I keep getting bashed and bullied by the media.”
Barrymore’s television career collapsed in the wake of the allegations, although he enjoyed a brief return to the spotlight during a stint on Celebrity Big Brother in 2006.
In 2009, the police watchdog published the findings of a review of the investigation into Mr Lubbock’s death, concluding that officers missed crucial evidence and did not ensure vital forensic tests were completed until six years later.