Williams harnesses inner He-Man as she targets return to form
The world number one was pictured with Arrow actor Colton Haynes, who appeared as Angelina Jolie's character from the movie Maleficient.
The duo was partying at the seventh annual Williams Invitational, where they were joined by friends and family for the 80s-themed celebrations over the weekend.
Williams' costume was no doubt a response to criticism she has received over the past few years about her muscular physique.
The 21-time Grand Slam singles champion will hope to draw strength from her inner superhero as she looks to bounce back from a difficult start to 2016.
Williams was defeated by Angelique Kerber in the final of the Australian Open and followed up with another final loss against Victoria Azarenka at Indian Wells.
Svetlana Kuznetsova knocked her out of the Miami Open in the fourth round, to leave Williams without a tournament success so far this year.
The 34-year-old starts the clay season at the Madrid Open on 29 April, followed by the Italian Open in Rome in May.
Williams then heads to Roland Garros, where she will bid to defend her French Open title.
She has won the Paris crown on three previous occasions – perhaps a fourth will be inspired by her new He-Man and the Masters of the Universe persona?