FEUSISBERG, Switzerland - Former World No.1 Martina Hingis has announced her pregnancy on her 38th birthday via social media yesterday.

"Thanks for all the birthday wishes!" the Swiss legend wrote. "Happy to share that this will be the last time we'll celebrate as a couple... excited to announce that we will become a family of three!"

Hingis, who was a five-time Slam champion in singles between 1997 and 1999 and who retired as the doubles World No.1 at the end of last year, married husband Harry Leemann in Bad Ragaz, Switzerland in July.

The 38-year-old was congratulated on social media by fellow members of the tennis community such as Sabine Lisicki and Judy Murray.