Senator Elizabeth Warren wants one of her biggest critics to face lawmakers in a hearing next week.

Warren, a progressive Democrat from Massachusetts, invites billionaire investor Leon Cooperman to testify on taxes before a Senate Finance Subcommittee hearing.

Cooperman confirmed in a response to CNBC that he had received the message and said he was considering Warren’s invitation. The senator asked Cooperman to confirm his attendance by Thursday.

In a letter to Cooperman, first received by CNBC, Warren urged the financier to attend a hearing organized and chaired by the Financial Responsibility and Economic Growth Subcommittee of the Finance Committee, which she chairs. The hearing, scheduled for April 27, will be titled Creating Opportunities through a Fairer Tax System.

Warren told Cooperman in the letter that she was interested in giving the longtime Wall Street executive “the opportunity to discuss my ultra-millionaire tax bill, which would level the playing field and narrow the racial wealth gap by bringing in the richest 100,000 American households surveyed. ” or the top 0.05% to pay their fair share. “The letter was sent to Cooperman on Monday.

A rivalry between Warren and Cooperman exploded during the Democratic presidential campaign. After proposing a property tax while in elementary school, Cooperman blew up her proposal in a letter to lawmakers.

“As much as it resonates with your base, your defamation of the rich is false, ignoring, among other things, the sources of their wealth and the essential contributions to society they are already making without your solicitation,” he said at the time.

A month later, Warren’s campaign ran a television commercial on CNBC targeting Cooperman and other business leaders. Her campaign also sold a mug that read “BILLIONAIRE TEARS” in response to a CNBC interview where Cooperman was crying.

Cooperman has since conducted numerous interviews ripping out Warren’s tax proposals, including a CNBC appearance in March advising viewers to buy gold if there is such a bill.

“When the wealth tax is over, go out and buy some gold because people will be rushing to find ways to hide their wealth,” Cooperman told CNBC at the time.

Cooperman was skeptical about Warren’s invitation on Tuesday.

“I’m trying to determine if she’s being objective or if she’s just trying to promote her own agenda,” Cooperman told CNBC in a statement. “I’m a little suspicious as she never replied to the letter I sent her earlier.”

Cooperman, who turns 78 two days before the hearing, is one of the most outspoken members of the investing community. He often speaks of his rags-to-riches story: he grew up in the South Bronx as a child of working-class Polish immigrants, attended public schools, and started his first job on Wall Street – at Goldman Sachs – with debt and no net worth.

After more than two decades with Goldman, Cooperman founded the hedge fund Omega Advisors in 1991. Today he is CEO of the Omega Family Office. Last year he signed the Giving Pledge, a commitment by the rich to donate much of their wealth to charity.

“That’s the American dream,” he said. “I want to give others the opportunity to live the American dream.”

Warren addresses Cooperman’s problems with her idea of ​​property tax in the letter sent Monday and encourages him to raise his concerns before her committee and those watching from home.

“But as we move quickly to examining changes to our manipulated tax laws so that the rich pay their fair share, I think you should be given the opportunity to present your perspective directly to Congress,” she writes to Cooperman. “The opportunity will allow you to express your views fully, not just in front of the financial news audience where you do express them often, but in front of the entire American people.”

Warren and other Democratic lawmakers have imposed a total annual tax of 3% on assets over $ 1 billion.

They have also called for a lower annual wealth tax of 2% on the net worth of households and trusts, which ranges from $ 50 million to $ 1 billion.

According to Forbes, Cooperman’s net worth is $ 2.5 billion.