Serena Williams has sparked major speculation that she's expecting baby number two. The 39-year-old tennis superstar dropped a massive swimsuit surprise on her Instagram this week, with melt-worthy and gorgeous photos of a trio swimsuit deal showing the former World no. 1 twinning in a pink Nike swimsuit with both 3-year-old daughter Olympian and a doll. The poolside photos bringing in some Qai Qai toy action came with the star's usual rock-hard muscles, but it looks like fans are spotting something else. Check it out below.