Donald Trump has threatened to invite Bill Clinton's former mistress Gennifer Flowers to Monday's debate.

The Republican nominee made the threat on Twitter Saturday afternoon after billionaire Mark Cuban, who supports Hillary Clinton, said he had received a front-row seat to the event.

'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!' Trump wrote.

Flowers replied promptly and said Saturday afternoon she had agreed to join Monday's debate.

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Donald Trump threatened to invited Gennifer Flowers to Monday's debate on Twitter Saturday afternoon after billionaire Mark Cuban said he had secured a front-row seat to the event

Hillary Clinton's campaign has confirmed they invited Cuban (left) to the debate and had given him the best seat possible. Bill Clinton testified in 1998 that he had sex with Flowers (right)

'Ms Flowers has agreed to join Donald at the debate,' her personal assistant told BuzzFeed.

Flowers seemed to respond to Trump's potential invitation directly on Twitter. An unverified account in her name, on which Flowers appears to have posted many photos and selfies, tweeted: 'Hi Donald. You know I'm in your corner and will definitely be at the debate!'

The message ended with a kiss emoji showing two lips.

Cuban meanwhile responded in a tweet of his own: 'Donald. Remember when you told me on the phone we were 'Bobbsie Twins' and I laughed ?'

He appeared to be referring to the Bobbsey Twins, a series of children's novels published throughout the 20th century. The books have since come under fire for being racist, especially through the portrayal of the family's cook, a black woman named Dinah.

Trump first misspelled Flower's first name, writing it with a 'j' instead of a 'g'. He deleted this first tweet and retweeted the same message, this with the proper spelling, as shown in grabs from The Hill.

Flowers seemed to respond to Trump's potential invitation directly on Twitter. An unverified account in her name posted this message on Saturday afternoon

Cuban responded in a tweet of his own: 'Donald. Remember when you told me on the phone we were 'Bobbsie Twins' and I laughed ?'

Bill Clinton testified under oath in 1998 that he had sex with Flowers, an actress and model. She had come forward in 1992 saying she had an affair with him during his time as governor from the late 1970s to the end of 1989.

He had previously denied having an affair with Flowers during a 1992 interview on 60 Minutes.

His wife's campaign told CNN on Friday that they had invited Cuban to the debate.

'He has the best seat we have access to,' an aide said.

Cuban owns the Dallas Mavericks, Landmark Theatres and film distributor Magnolia Pictures.

Trump's fellow billionaire and businessman Cuban announced he would attend the debate in a victorious tweet Friday (pictured)

He announced his presence at Monday's debate in a triumphant tweet Friday, writing: 'Just got a front row seat to watch @HillaryClinton overwhelm @realDonaldTrump at the 'Humbling at Hofstra' on Monday. It is on!'

He first hoped Trump, a fellow billionaire and businessman, could bring something new to the presidential campaign. But he was quickly disappointed.

'Trump scares me,' Cuban told CNN in July. 'Donald, initially, I really hoped he would be something different, that as a businessperson, I thought there was an opportunity there. But then he went off the reservation and went bats**t crazy.'

Cuban endorsed Clinton that same month. He has since called out Trump on multiple occasions.

A tweet posted by Cuban Thursday says Trump has 'no respect' for the second amendment.

Meanwhile preparations have begun for Monday's debate in Hempstead, New York. Pictured, workers install the set at Hofstra University