(Reuters) - Tennis superstar Serena Williams on Wednesday appeared to reveal she is pregnant, posting a photo of herself in a bathing suit on Snapchat with the caption "20 weeks." The 35-year-old, who will return to the No. 1 ranking in the world next week, later deleted the photo. Neither Williams nor her management team were immediately available for comment. If Williams is indeed 20 weeks into her term, that would mean she was approximately two months pregnant when she captured her record 23rd Grand Slam tournament title at the Australian Open in January. Her victory over older sister Venus Williams broke a tie with Steffi Graf for the most Grand Slam singles championships in the sport's modern era. Serena Williams has not played since, citing a knee injury. Williams announced her engagement to Reddit co-founder Alexis Ohanian last December. Other women have left the tour to have children and returned, including the Belgian player Kim Clijsters, who retired and had a child before coming back and winning three Grand Slam titles as a mother. Williams, who has played professionally for two decades, first gained the No. 1 ranking in 2002 and has held that spot for more than six years in total during her career. She is often regarded as the greatest female tennis player of all time. Venus Williams, 36, has won seven Grand Slam singles titles.