The idea of Donald Trump running for office is not so new — he was encouraged to seek election nearly 30 years ago by former President Richard Nixon.

Trump had appeared on Phil Donohue’s popular TV talk show in 1987 — and his performance dazzled Nixon’s wife, Pat, a new book, “Never Enough: Donald Trump and the Pursuit of Success,” reveals.

Four days before Christmas, the ex-president wrote a letter to the developer:

“Dear Donald, I did not see the program,’’ it said. “But Mrs. Nixon told me you were great.

“As you can imagine, she is an expert on politics and she predicts that whenever you decide to run for office, you will be a winner!”

He signed the letter with his “warm regards.’’

The book, by Michael D’Antonio, will hit stores Sept 22.