The wife of Republican presidential candidate NEWT GINGRICH is hiding a shocking lesbian secret!

Callista Gingrich – who carried on a seven-year extramari­tal affair with Newt before they wed – maintains an intimate friendship with an openly gay woman she’s known since high school.

“Callista is a great friend,” Karen Olson, a canon with the Min­neapolis-based Episcopal Church in Minnesota, told The ENQUIRER.

“I was a bridesmaid at her wed­ding to Newt, and I enjoy him immensely.”

The two women, who are both 45, grew up in White­hall, Wis., and went on to study music at Luther College in Decorah, Iowa. They both pledged the same sorority, Delta Alpha Delta, before graduating in the class of 1988, according to Olson.

“Callista and I go way back, and we had a lot of fun together,” she said.

“She knew I was a lesbian by the time we were at college and was fine with it. I’ve found her to be open-minded.”

In fact, helmet-haired Callista is so open-minded that she was Newt’s mistress while he was still married to his second wife Mari­anne, who recently blasted Gingrich in a highly publicized inter­view, saying he’d asked her for an “open mar­riage.”

But Olson leapt to his defense.

“I think Newt is funny,” she told The ENQUIRER. “He is certainly smart and has a thousand ideas. I enjoy him and I trust him.

“I think he values my friendship with Callista, and I consid­er him a good friend as well.

“We may differ on some realities of life, but that doesn’t change the fact that we can get past some of our differences.

“Would he get my vote? I’m considering all things.”

A top Washington political source believes that Newt and Callista’s relationship with Olson could hurt his run for the White House.

“This is a bombshell revelation exposing the fact that this woman has both Callista and Newt’s ear to pass on her beliefs,” said the source. “There’s now going to be questions as to who else may be in Callista’s secret circle of friends and can be of a major influence to Newt.”

Meanwhile, Newt, 68, was recently criticized for opposing gay mar­riage by his lesbian half sister Candace Gingrich-Jones, who said that she will be voting for President Obama.

Candace, a director at the gay advocacy group Human Rights Campaign, told MSNBC: “He is definitely on the wrong side of history when it comes to those issues.”

But Olson believes Newt may well get the support of gay voters.

“Are there people who are gay who will vote for him? Absolutely,” she told The ENQUIRER.

“Newt has been clear about saying he supports marriage be­tween a man and a woman, but he is certainly open to knowing that there are gay and lesbian people in the world.

“He’s in a relationship with many of them through his sister and myself and numerous other people who are close friends with Callista.”