Forty-two years later, Michael Apted finds it somewhat "ludicrous" how he started making documentaries about a group of British youngsters.
The latest, "49 Up" (8 p.m., Ch. 7), updates the lives of many of the people seen as 7-year-olds in "7 Up." And 14-year-olds in "14 Up." And so on and so on through this latest two-hour documentary.
(It's just making it to American TV two years after it aired in the United Kingdom.)
When the kids were chosen in 1964, it was "very random."
"It was only ever going to be one film, and it was mounted very quickly in about three weeks," said Apted, who, at the age of 22, was working on his first project. The goal was to demonstrate that the British class system was still in existence.
And, over the decades, the focus has changed.
"I think after its political beginnings at 7, 14, 21, it changed and outgrew that and then became much more about a humanistic document about people growing up," Apted said. "Which is why I think it's successful in other parts of the world, other than England."
The latest film updates the participants' lives. And takes a bit of a turn that Apted certainly didn't anticipate, although you could argue that he helped pave this road.
"This film is much more about them being in the film, which was not my idea. It was theirs," he said. "I have to think the 500-pound gorilla in the room was reality television, which didn't exist when we did '42 Up.'
"I think it made them really think about what in the (heck) are we into? That's always been a residual angle with them ... that they were railroaded into this by parents and schools and they suddenly woke up into adulthood and maturity and found they were in the middle of this juggernaut."
(It's not as popular here, but it "very much is part of the cultural heritage" in Great Britain.)
"There's some pretty sharp exchanges between me and them," Apted said. "They really kind of give me a roasting now and again about what the (heck) is this, and why should we be doing it."
Not that he intends to make "49 Up" the last in the series."I'll keep it going as long as I still got my marbles and maybe even beyond that," Apted said. "I mean, having got so far, it seems a pity to quit."