REGIS Philbin’s final answer: don’t expect him to do it again.

Regis is trying to manage expectations about the 10th anniversary, primetime edition of “Who Wants To be a Millionaire” he’s hosting this summer. Last time he did this, “Millionaire” was a ratings phenomenon.

“It was brand new then and it took a lot of people by surprise,” he told The Post over the weekend.

“Is it going to be as big a hit? I don’t know if it can be.

“The million-dollar payoff, which was really new in those days and has been copied since, is no longer the talking point.”

So Philbin and his producers hope to lure viewers with celebrity guests and more lifelines when his two-week, Sunday-to-Thursday night stint begins in August.

“We have seen celebrities on the show before, but [this time] one celebrity a night will answer just one question,” he reports. “And if he gets it right it is $50,000 to their favorite charity.”

A decade ago, Philbin’s original “Millionaire” earned ABC its highest ratings of the year before fans burned out from the quiz show’s multi-night scheduling.