Olympian's father hasn't reached his son yet.

Michael Phelps' estranged father Fred hasn't been able to directly offer his son congratulations or words of any sort since Michael won a record eight gold medals at the Olympics last week, says the New York Post.

"He's so busy, I'm sure not even his agent can get a hold of him," Fred told the paper.

"I'm very proud of him and all he's done," Fred added, noting that even though he didn't make the trip to Beijing, he "watched [Michael] every night on TV."

"This is not about me, it's about him," the retired Maryland state trooper said.

Fred divorced Michael's mother Debbie in 1992 and relatives tell the Post he's been "in and out of [his son's] life" since. The father and son briefly reconnected four years ago, says the paper, when Fred flew to Athens to watch Michael compete in the 2004 Olympic games.