Jennifer Aniston's secret half brother has been revealed as a "boho surfer."

Although the 43-year-old Hollywood star has never publicly spoken about Alex John Aniston, 22, he reportedly attended her Along Came Polly premiere in 2004 with his parents.

Alex and Jennifer share the same father, actor John Aniston, but his mother is actress Sherry Rooney.

Australia's New Idea magazine spoke to friends and neighbours of the young man whose sister is one of the most famous people in the world.

"He had a mattress in the back of his van, always had the same pair of pants with 20 patches on it and only had three shirts," Samantha Robles told the publication of the young man's lifestyle.

Alex apparently tries to keep his half-sister's identity a secret but people who live close to him in Santa Cruz, California, say that his father comes to visit him sometimes.

"I figured out who he was when one day I saw the dad turn up," former neighbour Rich Koslowski said. "I had friends out back and AJ and John were going through the garbage can. I talked to them briefly."

"I think he's very happy being off the radar," another neighbour added.