The civil lawsuit, first reported by TMZ and confirmed by ESPN, alleges that Kelli Tennant, a former host on Spectrum SportsNet LA -- the Lakers' regional sports network -- received an unwanted physical advance by Walton at a Santa Monica, California, hotel room.
The suit alleges that Tennant, who had a working relationship with Walton stemming from his time as a guest analyst on Spectrum, met with him at the Casa Del Mar Hotel to drop off a copy of her book, for which he provided the foreword, when he was in town on a road trip as an assistant coach with the Golden State Warriors.
According to the legal documents obtained by ESPN, Walton allegedly invited Tennant to his room so they wouldn't be seen together by any Warriors players. He then allegedly pinned Tennant to the hotel bed and forcibly kissed and groped her.
The suit also alleges that in May 2017, Walton "forced an aggressive hug" and made a lewd remark about Tennant's outfit at a charity event the two attended.
Tennant and her attorney, Garo Mardirossian, held a news conference on Tuesday. They issued a statement ahead of that news conference, noting in part: "As alleged in the lawsuit, Kelli Tennant, a former collegiate athlete and star sports broadcaster, is a woman who has had to tolerate and suffer in silence from the abuse she suffered at the hands of Luke Walton. By way of this lawsuit, Ms. Tennant is speaking out and saying #timesup to the culture of abusing women in the NBA."
Walton's attorney, Mark Baute, called the allegations "baseless.''
"The accuser is an opportunist, not a victim, and her claim is not credible,'' Baute said in a statement. "We intend to prove this in a courtroom.''
The Lakers said they were never told of the allegations when Walton was their coach and had no additional comment because he now works for another team.
"At no time before or during his employment here was this allegation reported to the Lakers," the statement read. "If it had been, we would have immediately commenced an investigation and notified the NBA. Since Luke Walton is now under contract to another team, we will have no further comment."
The Kings released a statement on Monday regarding the allegations.
"We are aware of the report and are gathering additional information," the statement said. "We have no further comment at this time."
The Warriors said they were also "aware of the alleged incident" and gathering additional information. Warriors guard Stephen Curry didn't offer much more when asked about his former coach on Tuesday.
"I know the team had a comment on it," Curry said. "That's pretty much all we can say right now. But in terms of Luke, I've known him for a long time, so hopefully everything works out."
The NBA released the following statement from spokesman Mike Bass on Tuesday: "We are coordinating with the Kings organization and are in the process of gathering more information."
Santa Monica police told the L.A. Times on Tuesday that they never received a report accusing Walton of sexual assault and are not currently investigating the allegations.
Walton and the Lakers "mutually parted ways," according to the team, on April 12, and he was hired by the Kings the next day.
Team sources told ESPN's Ramona Shelburne that the alleged assault occurred well before Walton joined the Lakers. "No one ever reported it to the team," a source said, "and that is not why the team parted ways with him."
The Associated Press contributed to this report.