SERENA WILLIAMS will not celebrate her daughter's one-year-old birthday - because she is a Jehovah's Witness.

The tennis star often posts photos to social media of her family life - but there won't be any party pictures from Alexis Olympia's special day.

9 Tennis star Serena Williams will not be uploading party pics to social media of daughter Olympia's first birthday - because of her religious beliefs Credit: Instagram @serenawilliams

9 Serena Williams gave birth to her daughter on September 13 last year - her first child Credit: Instagram @serenawilliams

Serena Williams is defeated in only 52 minutes to Britain's Johanna Konta in the Tennis Mubadala Silicon Valley Classic

Williams was asked about how she would be celebrating her daughter's birthday at a press conference at the US Open.

She replied: "Olympia doesn’t celebrate birthdays. We’re Jehovah’s Witnesses, so we don’t do that."

Jehovah's Witnesses do not celebrate religious holidays such as Christmas and Easter, and do not celebrate birthdays either.

They believe that these 'festivals' have pagan origins.

9 The tennis legend has revealed that her husband Alexis Ohanian has often 'taken the lead' in Jehovah's Witness upbringing Credit: Instagram @serenawilliams

9 Alexis Ohanian described his wife Serena as the greatest of all time as a sport star, a mother and a wife Credit: Instagram @serenawilliams

All about it... Jehovah's Witnesses THERE are more than eight million Jehovah's Witnesses in the world. The religious group is separate from mainstream Christian churches. Members follow an interpretation of the Bible taught by preacher Charles Taze Russell in Pennsylvania, US, in the late 19th century. They believe God will end the present world, which belongs to Satan, and create a new Kingdom to restore His original purpose on earth. Only 144,000 people will go to heaven, with others continuing to live on the new Earth and obey God, also called Jehovah. Many members quit their jobs and sold their homes and businesses after the organisation predicted Armageddon would come in 1975. Members are best known for preaching door-to-door and for handing out the magazines Watchtower and Awake! Famously they refuse blood transfusions, believing it is banned by Bible teachings, leading to court battles between parents and doctors treating sick kids.

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Williams married Reddit co-founder Alexis Ohanian in a lavish $1million ceremony in November last year at the New Orleans' Contemporary Arts Center.

Captioning a photo of the happy couple posted on Instagram, Ohanian wrote: "You are the greatest of all time, not just in sport--I’m talking about as a mother and as a wife."

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9 Serena Williams is already hitting the top of her game less than a year after giving birth to her baby daughter Credit: Instagram @serenawilliams

9 Alexis Olympia Ohanian Jr will turn one this week - but don't be expecting to see any party pics on social media Credit: Instagram @serenawilliams

9 Serena Williams spoke last year how her Jehovah's Witness beliefs are important but that she had 'never really practiced' Credit: Instagram @serenawilliams

Serena Williams' husband Alexi Ohanian uses their baby daughter Olympia as a football in brilliantly clip

And in an interview with Vogue magazine last year, 23-time Grand Slam winner Williams hinted that her husband is now practicing being her faith despite not coming from a religious upbringing.

She said: "Being a Jehovah’s Witness is important to me, but I’ve never really practiced it and have been wanting to get into it.

"Alexis didn’t grow up going to any church, but he’s really receptive and even takes the lead. He puts my needs first."

Serena prefers to call her daughter Olympia, and she told Vogue "we’re not spending a day apart until she’s eighteen".

9 Serena Williams, pictured hugging her father Richard Williams, with sister Venus to the left, is a 23-time Grand Slam winner Credit: Getty Images - Getty

9 Serena Williams has already reached the Wimbledon final not long after taking time off the court to raise a family Credit: Instagram @serenawilliams

Her husband, Alexis Ohanian is based in San Francisco and Williams admitted she found the idea of moving there and being a full time mum attractive.

However, she stated: "But not yet. I absolutely want more Grand Slams."

Serena has reached the final of Wimbledon in her first appearance at SW19 since becoming a mother.

She is currently competing in the US Open at the Billie Jean King National Tennis Center in New York.