Novak and Jelena Djokovic's alternative health views are under the spotlight after the tennis star and his wife both tested positive for COVID-19.
The Serbian superstar is the fourth player to test positive for the virus after competing in the Adria Tour. The tournament, which he organised amid the pandemic, was launched in Belgrade then moved to Zadar, Croatia on the weekend.
While Djokovic and his wife tested positive, their two children tested negative.
The pair have publicly stated their opposition to vaccinations, instead advocating for natural healing. Jelena also once posted an Instagram video suggesting she supports a false but prominent conspiracy theory that 5G is partly to blame for coronavirus.
Ben Rothenberg of The New York Times said the tennis star's "scepticism of science" no doubt contributed to his decision to push forward with the tournament during a global pandemic.
"I think that Djokovic's health opinions and views are probably a part of this; he has been sceptical about a vaccine," he told OTB Sports.
"He has brought all kinds of weird pseudoscience people on his channels, bringing on all kinds of strange gurus to talk about changing water with positive thinking and things like that.
"The scepticism of science did him no favours here."
He added: "When he talks about veganism and meditation, that is completely fine and is his prerogative to do. When he starts preaching more things that could be misleading and dangerous to people … is not a positive thing to be doing with his platform."
WHO IS JELENA DJOKOVIC?
Jelena Djokovic, 34, is a Serbian PhD candidate and humanitarian, who began playing tennis when she was a child.
After graduating from Sport High School in Belgrade, she went to Bocconi University in Italy, where she earned her master's degree. She later went on to earn a PhD in Management.
Jelena is now CEO of the Novak Foundation, an organisation that helps disadvantaged Serbian children, and the director of a Serbian magazine called Original.
Jelena is also an avid Instagram user, regularly posting photos with her husband and children.
HOW DID JELENA AND NOVAK MEET?
Novak and Jelena met when they were both students at Sport High School, where they both played tennis.
The pair began dating in 2005, and married in July 2014. They now have two children, Stefan and Tara.
In 2007, they launched the Novak Djokovic Foundation, which is dedicated to creating educational opportunities for disadvantaged children in Serbia.
HOW MUCH ARE THEY WORTH?
The pair are worth $US220 million ($A317 million).
WHAT IS THEIR STANCE ON VACCINATIONS?
Both Novak and Jelena have been open about their opposition to being vaccinated, including for COVID-19, instead advocating for natural healing.
Earlier this year, Novak reiterated he is against taking an anti-COVID vaccination if it becomes mandatory to travel once the pandemic subsides.
"Personally I am opposed to the vaccination against COVID-19 in order to be able to travel," he said in April.
"But if it becomes compulsory, I will have to make a decision whether to do it or not. This is my current feeling, and I don't know if it will change, but it really influences my profession."
WHAT EXACTLY DID JELENA SAY ABOUT 5G?
In April, Jelena shared a post which appeared to suggest 5G networks were to blame for coronavirus, just one day after Novak said he may refuse to take a COVID-19 vaccine.
She shared a 10-minute video to her 500,000 Instagram followers that largely focused on the conspiracy theory that 5G technology helped cause the pandemic.
Instagram's independent fact checkers subsequently labelled the video as "false information".
"What are your coronavirus thoughts?" she wrote in the caption. "Lots of videos going around these days debating the current situation with the #coronavirus, causes, cures, prevention … Whoever has time, please check this one out and let me know your thoughts. Does anyone recognise who this guy is? Kisses and love."
Jelena later released a statement saying: "I'm not claiming to be true or not, but I'm certainly interested in learning and getting informed about it."