LAST weekend, tennis ace Serena Williams stunned reporters at a press conference when she said she won’t be celebrating her daughter Olympia’s first birthday next month due to her Jehovah’s Witness faith.
“Olympia doesn’t celebrate birthdays,” the 36-year-old said. “We’re Jehovah’s Witnesses, we don’t do that.”
While for most of us our knowledge of Jehovah's Witnesses is their frequent door-knocking to try and convert you, a surprising number of celebs - including Serena's sister Venus and model Naomi Campbell - are followers or were raised in the faith.
And there are unusual rules members have to follow: they can't have life-saving blood transfusions, are unable to vote or date without chaperones being present - and are forbidden from having oral sex both in and out of marriage.
Celebrity followers going door-to-door
Serena and sister Venus were raised as Jehovah's Witnesses by their mother Oracene Price, who converted to the religion in the 1980s.
Serena has been more outspoken about the religion - which was started in the 1870s in the US - constantly thanking "Jehovah God" for her success as a tennis player.
In a recent Vogue interview she also 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 [Serena's husband] didn’t grow up going to any church, but he’s really receptive and even takes the lead. He puts my needs first.”
Legendary singer Prince, who passed away in April 2016, converted to the faith in 2001 following the death of his mother.
He described his conversion as: "a realisation. It's like Morpheus and Neo in The Matrix".
A committed Jehovah's Witness to the end, a memorial for the star took place at the Kingdom Hall of Jehovah's Witnesses near his Minnesota home to commemorate his life.
Canadian model Coco Rocha has opened up about her life as a devout Jehovah's Witness saying: "faith is everything" and despite her fame, she still preaches door-to-door.
"The whole purpose is to inform people. Some people think we’re a pushy religion, but if you’re not interested, just say so," she explained to luxury magazine Dujour.
Naomi Campbell's mum Valerie is also a follower, telling Vogue: "I brought up Naomi as a Jehovah's Witness, but she must choose her faith for herself. I do give her literature on the subject though when she asks for it."
However, the model has not followed in her mother's footsteps by becoming a believer.
Other A-list celebs, including Janet Jackson, Ja Rule and actress Michelle Rodriguez were raised in the faith as children, but no longer practise it.
What do Jehovah's Witnesses believe?
Members follow their own version of the Bible called the New World Translation of the Holy Scriptures.
They say our world now belongs to Satan, and because of this God - who they call Jehovah - will end it very soon in order to create a new kingdom.
Jehovah's Witnesses are not meant to make friends with people of other faiths, as non-believers are considered to belong to "Satan's world" - although this isn't always strict as their celebrity followers show.
Many followers say there is a a sense of community that can come with being a Jehovah's Witness - as they are tight-knit and have respect for each other.
The easy-to-follow belief system is also a big draw for people interested in the faith, and the organisation has a lot of literature providing what they believe to be the answers to life's big questions.
A Jehovah's Witness Kingdom Hall: followers of the faith reject blood transfusions as they are seen as 'sinful'
Jehovah's Witnesses are barred from having blood transfusions - which makes operations like Caesarean sections - that often require them - more difficult to complete, as blood products are linked to immorality.
As one Jehovah's Witness told the New Yorker: "It’s as much a sin to take a blood transfusion as to have an extramarital affair".
This has led to several deaths - and various court battles between Jehovah's Witnesses and doctors seeking to treat them.
Last Autumn, a 27-year-old Canadian new mother, Éloïse Dupuis, died a week after giving birth due to haemorrhaging - but despite doctors' pleas for her to have a blood transfusion she refused.
Jehovah's Witnesses don't believe in sex before marriage - and dating isn't condoned unless they bring along a chaperone as well.
So it's likely that the first person you choose to date will be the person you marry.
And after marriage, there's still restrictions on sex - namely anal and oral sex which are strictly forbidden, something that is also frowned upon in religions such as Islam and other forms of Christianity.
Followers are peaceful - even refusing military service - but are suffering from persecution in some countries.
Earlier this year, they were declared as an "extremist group" in Russia with raids on their Kingdom Halls and several arrests - it's thought hundreds have fled the country and applied for asylum in Finland since.
Other things they are prohibited from doing include being patriotic, as it is seen as "worshipping an idol", or voting or canvassing for political parties as they remain politically neutral.
As Jesus never celebrated his birthday, Jehovah's Witnesses don't mark theirs' either, and they don't acknowledge the major Christian holidays of Christmas Day or Easter, as they believe these festivals are based on pagan customs.
On the plus side, it means they probably save a lot of money due to not having to fork out for expensive gifts.
Beliefs in the end of the world - and controversey
Their beliefs in the end of the world have led to a series of unfulfilled prophecies.
In 1975 they were told the world would end and members were encouraged to preach full-time and get rid of their possessions.
Thousands of them quit their jobs and sold their homes - but Armageddon didn't come leading to a drop in membership, something which has remained in decline ever since.
Armageddon was also promised before the start of the Millennium, but again never materialised.
There has also been other controversies: the Charity Commission are currently investigating claims that some followers were abused as children by fellow members of the faith.
Members are known for their recruitment drives: previously, they would go door-to-door to try and recruit new converts, handing out literature that explains their beliefs.
However, people who have left have described this as being "exhausting".
One said: "I barely got any sleep when I was a Witness...I needed the weekends to catch up on my sleep debt, but instead I had to get up at the crack of dawn to go out preaching.
