Serena rocked a bright yellow midi skirt (complete with a poodle), saddle oxfords, and a black crop top that accentuated her baby bump.
Williams' guests also got into the theme: Longoria wore a red-and-black polka dot dress and a high ponytail, while Ciara wore a gray poodle skirt with a pink poodle on the side.
Chinese, North Korean foreign ministers hold talks at Manila meeting
Ties have grown frostier between Beijing and Pyongyang, which has openly criticized China for siding with the USA on sanctions. With the US, Japan and South Korea expected to push for stronger actions against the North, a verbal showdown loom.
Serena's baby shower was held at the old-fashioned Nick's 50's Diner, and the celebrities dressed up in brightly coloured 1950's-style attire for the occasion.
The women posed with a vintage jukebox and period jalopy, posting pictures to social media with the hashtag #ShakeRattleandRoll2017.
And last month, Serena's fiancé, Reddit co-founder Alexis Ohanian, spoke on NBC's Squawk Box how he predicted Serena would be as a future mum. They have yet to find out whether they're having a boy or girl, but Ohanian revealed on Jimmy Kimmel Live! that the couple has a "hunch" that Williams will deliver a baby girl.
News. She was later featured on the August cover of Vanity Fair, exposing her baby bump while her profile covered the fact that she was in shock about her pregnancy news.