The organizers announced that they expect the presence of Williams, winner of 23 major tournaments.
The 37-year-old has raised a prestigious trophy most recently in 2017 in Australia.
Williams took part in the Auckland tournament in 2017, losing in the second round to Madison Brengle.
The American has been slowed down by injuries lately.
She did not play at the Cincinnati tournament, citing back pain that led her to retire from the Rogers Cup final in Toronto.
The Associated Press