The latest claims of impropriety during Kavanaugh's youth came as he was already facing a dramatic hearing where his testimony was to be weighed against that of a university professor who has separately accused him of assault.
Senate Democrats are now investigating a bombshell claim by Deborah Ramirez, 53, who says Kavanaugh sexually assaulted her during a 1980s college party at Yale University.
Kavanaugh denied the story, calling it "a smear, plain and simple."
Like Christine Blasey Ford, the professor accusing him of assaulting her when they were teenagers, Ramirez wants the FBI to investigate the incident, and Democratic lawmakers are backing their demands.
Ford, meanwhile, agreed to testify Thursday after an increasingly ugly weeklong standoff that saw her forced to leave her California home as she faced death threats and the president openly attacked her credibility.
Kavanaugh, who strongly denies the allegation, said he wishes to testify as soon as possible to clear his name following Ford's claims that he attacked her at a 1980s high school party.
According to The New York Times, the federal judge has calendars from the summer of 1982 he plans to share with senators showing he was out of town most of that time with no indication of the party of concern.
The two parties will testify separately -- first Ford, followed by Kavanaugh's response -- the Senate Judiciary Committee confirmed.
On Sunday, Senator Dianne Feinstein, the top Democrat on the judiciary committee, urged the panel to halt proceedings in light of the latest allegation.
"I am writing to request an immediate postponement of any further proceedings related to the nomination of Brett Kavanaugh," she said in a statement.
"I also ask that the newest allegations of sexual misconduct be referred to the FBI for investigation, and that you join our request for the White House to direct the FBI to investigate the allegations of Christine Blasey Ford as well as these new claims."
Meanwhile, Democratic senator and committee member Richard Blumenthal echoed demands for an investigation.
"The Senate simply cannot in good conscience vote on this nomination without a full fair FBI investigation of all these allegations," he said.
