To Alexis Ohanian, his wife Serena Williams is the "Greatest Momma Of All Time."

On Monday, Feb. 26, while on her way to Indian Wells, California, where she will compete in the 2018 BNP Paribas Open in March, the tennis pro saw AdQuick billboards featuring her and her 5-month-old daughter, Alexis Olympia Ohanian Jr.

According to People, Ohanian commissioned four billboards in honor of Williams's competitive return to tennis, but the real kicker is that the athlete had no idea that they were going up.

The entrepreneur and chairman of Reddit took to Instagram to share four photos of the oversized images.  

"These just went up alongside 1-10 into Palm Springs. @olympiaohanian & I wanted to welcome her back to tennis. Designed them myself, with some help from Jr. #GMOAT," the 36-year-old wrote

Serena Picks Up Tennis Rack

Aside from surprising his wife with the heartfelt roadside images, Ohanian has been cheering on his wife on the sidelines ever since her return to the sport. 

As previously reported, Williams decided to return to tennis five months after giving birth to Alexis Olympia in September 2017. The 23-time grand slam singles champion played alongside her sister Venus Williams as they competed for the United States against the Netherlands. This was the 36-year-old's first competitive match since 2015 and the first time the sisters have been on Team USA in three years. 

Williams was originally scheduled to compete in January to defend her title but withdrew from the competition 12 days before the event. 

Shortly after, Williams revealed that she felt as though she was super close but not personally where she wanted to be. 

"My coach and team always said, 'Only go to tournaments when you are prepared to go all the way," Williams said in a statement. 

Alexis Olympia Ohanian Jr. 

Williams and Ohanian welcomed their first child together, Alexis Olympia Ohanian Jr., on Sept. 1, 2017. 

In an interview with Vogue, the tennis pro said that she felt that Alexis had made her stronger and had helped her anxiety disappear when she lost matches. 

"Knowing I've got this beautiful baby to go home to makes me feel like I don't have to play another match. I don't need the money or the titles or the prestige. I want them but I don't need them. That's a different feeling," Williams explained