Republican presidential candidate Donald Trump may have pulled his most crass act yet.

The latest Trump stunt follows Hillary Clinton’s decision to invite Mark Cuban, a fellow billionaire and Trump rival, to Monday’s presidential debate.

This prompted Trump to say: “If dopey Mark Cuban of failed Benefactor fame wants to sit in the front row, perhaps I will put Gennifer Flowers right alongside of him!”

Flowers had an affair with Clinton’s husband, former President Bill Clinton.

Flowers confirmed she will attend Monday night’s debate (broadcast in Australia on Tuesday) in a text message to The New York Times: “Yes I will be there.”

Gennifer Flowers says she’ll be at the presidential debate. Photo: AAP

Clinton’s campaign spokeswoman Jennifer Palmieri responded: “Hillary Clinton plans on using the debate to discuss the issues that make a difference in people’s lives.”

She added: “It’s not surprising that Donald Trump has chosen a different path.”

Trump has been criticised throughout the campaign for crass comments he has made about women in the past, including insults about their physical appearance.

Clinton’s campaign has tried to capitalise on those comments, including with a new advertisement that features images of adolescent girls looking at their reflections as audio of Trump’s comments play.

The new drama underscores the challenges Trump faces as he attempts to close his deficit among female voters, whom polls show favour Clinton by significant margins.

Trump had all but ignored issues such as child care and maternity leave until the Republican National Convention when his daughter, Ivanka, suddenly said her father would work to provide affordable childcare for women.

If dopey Mark Cuban of failed Benefactor fame wants to sit in the front row, perhaps I will put Gennifer Flowers right alongside of him!

— Donald J. Trump (@realDonaldTrump) September 24, 2016

Trump says he’d do more to help women from the White House than Clinton, a lifelong champion of women’s rights who would become the nation’s first female President.

“My opponent likes to say that for decades she’s been fighting for women, that she’s been fighting for children,” Trump said at a rally in Roanoke on Saturday.

“Why, then, are 70 million American women and children living in poverty or on the brink of poverty in our country?

“For years she’s been doing this and she’s done nothing.”

With AAP