I never was able to get to the weight I needed to be no matter what I did, no matter how much I trained,” the tennis legend says in a new interview.

Serena Williams showed off her slim figure in a bold swimsuit after revealing she’s been using a weight-loss medication. The athlete, 43, sported a bright yellow one-piece as she posed for a series of snaps Thursday. “melanin mellow-yellow ,” she captioned the Instagram carousel — and fans were quick to hype her up in the comments.