Serena Williams didn't mean to announce her pregnancy via Snapchat.

The 35-year-old professional tennis player revealed earlier this month that she is expecting a baby with her fiancé Alexis Ohanian when she took to the photo sharing app to post a snap captioned "20 weeks".

Now, the star has admitted she meant to save the photo for later use, and didn't mean to publish it for the world to see.

She said: "Well, actually it was an accident. I was on vacation just taking some time for myself and I have this thing where I've been checking my status and taking pictures every week to see how far along I'm going.

"I didn't tell a lot of people to be quite honest and I'd been saving it. And you know how social media is when you press the wrong button ... and [there it was]."

But Serena admits it wasn't the end of the world, as she was planning on breaking the news a few days after her mishap anyway.

She added: "So thirty minutes later, my phone doesn't ring that much, and thirty minute later I missed like four calls and I'm like, 'That's weird,' and then I picked it up and I was like 'Oh no' ... but it was a good moment. I was just going to wait literally just five or six more days so that's okay."

Meanwhile Serena - who defeated her sister Venus to be crowned winner of the Australian Open in January - says she's been "fortunate" enough to not suffer with morning sickness so far, and said despite her pregnancy her tennis career is far from over.

Speaking to Gayle King during her TEDtalk in Vancouver on Tuesday (25.04.17), Serena said: "I've been so very fortunate. I haven't [had any sickness]. Obviously I'm going to have a baby and I'm going to stay fit and kind of come back and play tennis and keep working on my fashion line. That would be really fun."