Serena Williams sent a message - literally - that she was back on the practice court on Tuesday, updating the world via Twitter that one of the WTA's greatest legends is hopefully on her way back to the sport after a lengthy lay-off.

Williams hasn't played since winning Wimbledon last July, a series of health problems, which includes an injured foot and a pulmonary embolism, keeping her away from competition. But through Twitter, where she has more than 2,000,000 followers, she has told the world she's hitting again.

"Cool news guys stay tuned... I'll update you with a pic... You ready?" she Tweeted, then later wrote with more, including a photo of her on the practice court in a pink outfit. "Look who I spotted on the court. Her first day back..."

Check out Williams' Twitter account by clicking here!

Williams is a 13-time Grand Slam champion, winning five Australian Opens, four Wimbledons, three US Opens and one French, and she was No.1 for 123 weeks. She also has 12 Grand Slam doubles titles (all with Venus Williams) and two Grand Slam mixed doubles titles (both with Max Mirnyi).