TMZ Sports news outlet initially broke the story regarding the lawsuit, which was sparked by an alleged incident that occurred before Walton became the head coach of the Los Angeles Lakers in April 2016.
ESPN, citing anonymous sources, reported that the NBA opened an investigation into the matter.
The report includes a summary of legal documents acquired by TMZ Sports that say Tennant, who says she knew Walton for "several years," met Walton at his Santa Monica hotel to discuss him writing a foreword for a book she had been working on.
She alleges that he convinced her to come up to his hotel room, where he groped her and forced himself on her before eventually letting her go.
Following the incident, Tennant claims that Walton continued to verbally and physically harass her, according to a report.