Aussie pool queen Ariarne Titmus reveals her VERY surprising link to Queen Mary of Denmark - who'll be watching her race in Paris

Champion Australian swimmer Ariarne Titmus has revealed that she's related to Queen Mary of Denmark - and that her cousin Mary and King Frederik will be poolside to watch her race in Paris.

Titmus, the reigning Olympic 200m and 400m freestyle champion, is a proud Tasmanian, just like Queen Mary - but that's not the only thing they share.

'We're actually cousins in a distant, roundabout sort of way,' she revealed to Woman's Day. 

'One of dad's cousins is married to Mary's cousin, which is actually pretty funny considering the running joke that everyone born in Tasmania is somehow related!' 

The royal couple will also both be poolside in Paris when Titmus competes in the 400m freestyle final on July 28 in one of the first must-watch events for Aussies after Saturday morning's opening ceremony.

'It's been in the works for months, and all had to be hush-hush due to security concerns,' explained Titmus's father Steve.

'The 400m women's final is regarded as the race that will stop the nation - and having a king and queen cheering on our Arnie - it doesn't get much better.'

Titmus says she's grateful for all the support, but won't have much time to stick around to meet the royals after the race.

'Mary may want to hang out after the race, so I hope she's OK if I duck off and not stay and mingle,' she said.

'I have to rest up for the next morning when I'm back for the 200m freestyle heats - I think she will understand.' 

Meanwhile, Titmus says she has never felt better prepared for any swim meet just days out from defending her Olympic titles.

'There's not much room for anything in your head other than focusing on the task at hand,' Titmus told reporters at Australia's swim team camp in Chartres, about 95km south-west of Paris.

'If you let external noise come in, you get off track.

'For me, I have a massive program coming up with a lot of expectation on myself, from myself and I know the Australian public.

'And if I let external factors enter my mind it's exhausting so I really just think about swimming as fast as I can.'

Titmus's double gold at the Tokyo Olympics three years ago came after a preparation limited by a shoulder injury.

Her path to Paris has been smooth, highlighted by breaking the 200m freestyle world record at Australia's selection trials last month.

Titmus also holds the 400m world benchmark, set at last year's world championships.

'Mentally I have got so many learnings from the last Olympic Games,' Titmus said.

'I know this is going to be different with big crowds, which I am very excited for.

'As an athlete - altogether, as a whole - I am in a better position than three years ago.

'I am being honest in saying I think I have prepared the best I ever have for a swim meet.

'So more than anything I'm just excited to see what I am capable of.

'Of course I am racing for our country and for the swim team and for myself and my family.

'But it's about trying to get the best out of yourself, that is why I still swim because I believe I have got more in the tank.

'That is my goal at these Games, to try and get every skerrick out of myself.'

Titmus's highly anticipated 400m race against American great Katie Ledecky and Canadian teen Summer McIntosh comes on the opening day of competition at the Paris pool, July 27.