Marianne Gingrich, seen here in 1995 with her former husband Newt Gingrich,  is expected to discuss her relationship with the presidential hopeful in an interview airing on Thursday, days before the South Carolina primary.

Story highlights

The Gingrich campaign releases a "Memo to ABC News Leadership"

It is from his daughters from a first marriage

ABC News says the interview with Marianne Gingrich is set to air Thursday night

Columbia, South Carolina CNN  — 

Newt Gingrich’s adult daughters are coming to their father’s defense ahead of a potentially damaging interview with his second wife scheduled to air two days before the Republican South Carolina primary.

The Gingrich campaign released a “Memo to ABC News Leadership” from daughters Kathy Lubbers and Jackie Cushman. The memo addresses reports Wednesday evening of the network’s extensive interview with the Republican presidential candidate’s ex-wife.

CNN confirmed with ABC News that the interview with Marianne Gingrich is scheduled to run Thursday evening on “Nightline.”

ABC News would not comment on The Drudge Report exclusive that said “her explosive revelations are set to rock the trail.” The network will likely release excerpts in advance of the evening program.

Lubbers and Cushman, daughters from Gingrich’s first marriage to Jackie Battley, have both been out on the campaign trail extensively with their father, his two grandchildren and wife, Callista. In the statement, the daughters refer to the failure of a marriage being a “terrible and emotional experience for everyone involved.”

“Anyone who has had that experience understands it is a personal tragedy filled with regrets, and sometimes differing memories of events,” the statement said. “We will not say anything negative about our father’s ex-wife. He has said before, privately and publicly, that he regrets any pain he may have caused in the past to people he loves.”

The daughters allude to questions about the timing of the interview’s potential release, which reportedly could have a negative impact on their father. In recent days, Gingrich has picked up considerable ground in South Carolina, according to the latest CNN poll.

“ABC News or other campaigns may want to talk about the past, just days before an important primary election. But Newt is going to talk to the people of South Carolina about the future- about job creation, lower taxes, and about who can defeat Barack Obama by providing the sharpest contrast to his damaging, extreme liberalism. We are confident this is the conversation the people of South Carolina are interested in having.”

CNN’s Ashley Killough contributed to this report.