How celebs do Christmas! Karl Stefanovic delivers presents on a scooter as Rita Ora strips down to a festive bikini ...

Christmas comes but once a year - and some of Australia's most recognisable faces are sharing their celebrations with their family and friends on Instagram.

On Saturday, Today host Karl Stefanovic shared a photo of himself about to set off on a scooter with his mother Jenny in the passenger seat while carrying a Santa sack.

He wrote in the caption of the post: 'Well it was a busy night delivering but I hope all you kids are happy. Well done to all the Mrs Claus out there. Merry Christmas,' he added.

Spreading Christmas cheer: Karl Stefanovic celebrated Christmas delivering presents on a scooter with his mother Jenny who carried a sack of presents

The Voice coach Rita Ora, 31, put on a raunchy display as she soaked up the summer sun in a festive bikini.

The British pop star, who is in Sydney with her filmmaker boyfriend Taika Waititi, flaunted her sensational figure in an orange sequin two piece, with the caption: 'Merry Christmas. I love you.'

In another photo, the singer smiled as she showed off her backside along with the caption: 'Wait is Xmas dinner ready?'

Sophie Monk beamed for a festive selfie with her fiancé Joshua Gross as they dressed in Santa themed outfits with their adorable golden retriever puppy Bluey.

Sizzle! The Voice coach Rita Ora put on a raunchy display as she soaked up the summer sun in a festive bikini. She flaunted her sensational figure in an orange sequin two piece, with the caption: 'Merry Christmas. I love you'

Ready to feast! In another photo, the singer smiled as she showed off her backside along with the caption: 'Wait is Xmas dinner ready?'

All that sparkles! In another racy photo, Rita put on a cheeky display as she showed off her sequined bottoms 

'Our First Family Christmas': Sophie Monk beamed for a festive selfie with her fiancé Joshua Gross as they dressed in Santa themed outfits - Mr and Mrs Claus - with their adorable golden retriever puppy Bluey

Joshua shared the photo and wrote in the caption: 'Our First Family Christmas. Hope Santa was good to you all.'

Rebel Wilson shared a selfie with her sisters Liberty and Annachi Wilson as they dressed in matching pyjamas and enjoyed some quality family time together.

Model Kris Smith spent the morning with his fiancée Sarah Boulazeris and daughters - Mila, three, and Frankie, two - opening their presents.

Matching! Rebel Wilson shared a selfie with her sisters Liberty and Annachi Wilson as they dressed in matching pyjamas and enjoyed some quality family time together

Christmas gifts: Model Kris Smith spent the morning daughters - Mila, three, and Frankie, two - opening their presents

Sweet! Kris also shared a photo of fiancée Sarah Boulazeris and their daughters 

Nova radio star Kate Ritchie shared a selfie with her pet dog and in the caption, sent her season's greetings to her followers.

Former Bachelorette Georgia Love and her husband Lee Elliot wore matching pyjamas and smiled for a photo with their cat Pawdrey Hepburn in front of their festively decorated tree and their dozens of presents. 

AFL star Gary Rohan's ex-wife Amie smiled for a photo with her daughters - Bella, three, and Sadie Rose, one - dressed in adorable matching pyjamas in front of their tree. 

Festive pup: Nova radio star Kate Ritchie shared a selfie with her pet dog and in the caption, sent her season's greetings to her followers

Tis the season! Former Bachelorette Georgia Love and her husband Lee Elliot wore matching pyjamas and smiled for a photo with their cat Pawdrey Hepburn in front of their festively decorated tree and their dozens of presents

Sweet: AFL star Gary Rohan's ex-wife Amie smiled for a photo with her daughters - Bella, three, and Sadie Rose, one - dressed in adorable matching pyjamas in front of their tree

Locky Gilbert and Irena Srbinovska shared a festive meal with fellow Bachelor alum Alisha Aitken-Radburn and Glenn Smith.

Irena wrote in the caption: 'Whilst I am missing home and my family. I am so grateful to have such amazing friends here in Perth.'

Fiona Falkinier also posed for a photo with her partner Hayley Willis and their son Hunter beaming in front of their Christmas tree.

Quality time: Locky Gilbert and Irena Srbinovska shared a festive meal with fellow Bachelor alum Alisha Aitken-Radburn and Glenn Smith. Irena wrote in the caption: 'I am so grateful to have such amazing friends here in Perth'

Festive family: Fiona Falkinier also posed for a photo with her partner Hayley Willis and their son Hunter beaming in front of their Christmas tree

'So much joy today feeling so blessed to have our little man here with us for his first Christmas,' she wrote in the caption.

Christian Wilkins shared a hilarious selfie with Santa, who on the second look was in fact his father, Today entertainment editor Richard Wilkins.

'I KNEW Santa looked familiar!! Merry Christmas you filthy animals,' the model wrote in the caption. 

'I KNEW Santa looked familiar!': Christian Wilkins shared a hilarious selfie with Santa, who on the second look was in fact his father, Today entertainment editor Richard Wilkins