Serena Williams' husband Alexis Ohanian celebrates her return to tennis with billboards

Serena Williams is returning to the tennis tour six months after giving birth to daughter Alexis Olympia, and her husband, Reddit co-founder Alexis Ohanian, welcomed her back with four giant billboards along Interstate 10 heading into Palm Springs, California.

The billboards feature photos of Williams and the baby, with the caption "G.M.O.A.T.", or ''Greatest Momma of All Time''.

Williams is scheduled to play next week at Indian Wells, California, and has been granted a wild card into the 2018 Miami Open in Key Biscayne from March 19-April 1.

The 23-time grand slam champion has won a record eight Miami Open singles titles, and joins a field that includes 20-time grand slam winner Roger Federer, 78 of the top 79 ranked men and 75 of the top 76 ranked women. Federer is coming off an Australian Open title, as is Caroline Wozniacki, who regained the world No. 1 ranking in Williams' absence.

Others entered in the Miami Open include: world No. 1 and 16-time grand slam champion Rafael Nadal, 12-time grand slam champion and six-time Miami Open winner Novak Djokovic, three-time grand slam champion Stan Wawrinka, and former US Open champions Juan Martin del Potro and Marin Cilic. Cilic is coming off a finals appearance at this year's Australian Open.

The women's field features seven-time grand slam champion Venus Williams, five-time grand slam champion Maria Sharapova, two-time grand slam winner and defending Wimbledon champion Garbine Muguruza, reigning French Open champion Jelena Ostapenko, 2017 US Open winner Sloane Stephens, Olympic gold medallist and Miami native Monica Puig, and two-time grand slam winner Angelique Kerber.

Williams had planned her return from maternity leave at the Australian Open, but withdrew saying she wasn't ready yet.