Alexis Ohanian homage to his tennis superstar wife Serena Williams with four billboards declaring her the greatest of all time.

Williams is arguably the best female tennis player ever, but Ohanian is singling out her mothering skills. The four billboards, which line the Palm Springs highway, proclaim Williams as the “GMOAT,” or the greatest momma of all time. Williams and Ohanian welcomed their first baby, daughter Alexis Olympia, in September, and married two months later.

The billboards, which prominently feature 5-month-old Alexis Olympia, was Ohanian’s way of wishing Williams luck as she returns to tennis for the first time since giving birth. She’ll compete at the BNP Paribas Open in Indian Wells, Calif. starting next week.

“These just went up on alongside I-10 into Palm Springs,” Ohanian tweeted. “@OlympiaOhanian & I wanted to welcome her back to tennis. Designed them myself, with some help from Jr.”

 Williams was eight weeks pregnant when she won the Australian Open in January 2017. She took a leave from the sport after that victory, the 23rd Grand Slam singles title of her career. She is one major title victory away from tying Margaret Court for most Grand Slam trophies.