Martina Navratilova has announced she is cancer-free, with Billie Jean King welcoming the "wonderful news".

Doctors believe the 66-year-old tennis great has beaten cancer for a second time, after previously overcoming breast cancer in 2010.

The Czech-American announced in January she had been diagnosed with throat and breast cancer, sparking an outpouring of well-wishes.

She is one of the most decorated players of all time, having won 18 grand slam singles titles between 1978 and 1990, plus a staggering 41 doubles slams.

Speaking to Piers Morgan on TalkTV, Navratilova said: "As far as they know, I'm cancer-free."

According to The Sun, Navratilova will have further preventative radiation treatment on her breast.

"Then I should be good to go," she said.

King, her friend and former tennis rival, was thrilled to learn Navratilova's health has taken a turn for the better.

She wrote on Twitter: "Such wonderful news from my dear friend, ⁦@Martina⁩. We are so happy for you!"

Speaking to Stats Perform prior to Navratilova's announcement, former ATP world number two Tommy Haas spoke of his admiration for the legendary left-hander, and wished for a full recovery.

"What she has done in women's tennis and her success, the way she also kind of showcased her athleticism, her focus, her dedication to the sport, the records that she's broken, the longevity of it too," Haas said, listing reasons to be an admirer.

He described her as "an icon on the tour", and hoped she would survive this year's worrying cancer scare.

"Obviously, when you read the news about anyone in the tennis world that has had some kind of impact, or a great career, it's always sad, and you send them a text message, and you wish them the best and a speedy recovery," said Haas, the Indian Wells Open tournament director.

"You hope that they found these situations early, just like with Chris Evert [who recovered from ovarian cancer], and that they get through this and that they have the loved ones and friends around them and support them and get back to what they enjoy doing in life.

"I think we all know, and realise that without health, you have nothing. It's nice to be a part of certain things that you're passionate about. And it's important, and it's great, but being healthy and doing the things that you want to do ultimately, is really what it comes down to."