The tennis star's baby shower was held Saturday at Nick's 50's Diner in West Palm Beach, Florida, and had a 1950s theme, with the mother-to-be sporting a pompadour, poodle skirt and black-and-white saddle shoes.
Williams, 35, expecting her first child with her fiance, Reddit co-founder Alexis Ohanian, posted tons of amazing photos to Instagram and Snapchat, letting fans in on her big day.
Her celebrity friends, Eva Longoria, Ciara, Kelly Rowland and La La Anthony, also got in on the theme, according to photos posted online. Williams' big sister, Venus, was also on hand to fete "Baby O."
Williams and Ohanian, 34, announced they were expecting back in April, which was approximately four months after the two revealed on Williams' verified Reddit account that she and Ohanian were engaged.