Avenatti made the announcement on Twitter Wednesday morning, naming his client as Julie Swetnick. In the tweet, he described her as courageous, brave and honest.
Here is a picture of my client Julie Swetnick. She is courageous, brave and honest. We ask that her privacy and that of her family be respected. pic.twitter.com/auuSeHm5s0— Michael Avenatti (@MichaelAvenatti) September 26, 2018
Below is my correspondence to Mr. Davis of moments ago, together with a sworn declaration from my client. We demand an immediate FBI investigation into the allegations. Under no circumstances should Brett Kavanaugh be confirmed absent a full and complete investigation. pic.twitter.com/QHbHBbbfbE— Michael Avenatti (@MichaelAvenatti) September 26, 2018
The attorney also tweeted images of what he said was a sworn statement from his client, adding, "Under no circumstances should Brett Kavanaugh be confirmed absent a full and complete investigation."
Two other women have come forward with allegations of sexual misconduct against Kavanaugh.
MORE: 2nd woman claims sexual misconduct by Supreme Court nominee Brett Kavanaugh
California professor Christine Blasey Ford has also accused Kavanaugh of sexually assaulting her at a high school party. Deborah Ramirez has also come forward with accusations against Kavanaugh. Ramirez said in a story published Sunday by The New Yorker Magazine that Kavanaugh placed his penis in front of her and caused her to involuntarily touch it during a drunken dormitory party.
Kavanaugh has staunchly denied that he ever sexually assaulted anyone.
In a statement just released, Kavanaugh said, "This is ridiculous and from the Twilight Zone. I don't know who this is and this never happened."
His allies, including President Donald Trump, have cast doubt on the accusations.
Avenatti is a third rate lawyer who is good at making false accusations, like he did on me and like he is now doing on Judge Brett Kavanaugh. He is just looking for attention and doesn’t want people to look at his past record and relationships - a total low-life!— Donald J. Trump (@realDonaldTrump) September 26, 2018
Ford and Kavanaugh are expected to testify separately at a committee hearing on Thursday.
The Associated Press contributed to this report.