IT was a family affair for Australian celebrities yesterday.
From Kate Ritchie, who spent the day at the Sydney Opera House with her daughter Mae,to footy star Beau Ryan who celebrated on the harbour alongside his wife Kara and young daughter Remi, many Aussie celebrities marked the occasion with a social media post. 
Jessica Mauboy's stylist posted an image of the Darwin-based singer ahead of her performance of the national anthem, in English and an indigenous dialect, on the Harbour Bridge.
Miss Universe Australia Monika Radulovic posted a snap of herself brandishing an Australian flag in front of the bridge, writing: "So proud to be a part of the best country in the universe." Model sisters Ash and Jess Hart, both based in the US, shared pictures of themselves enjoying the Aussie lifestyle. Jess posted a throwback snap of herself on the cover of the now-defunct Madison magazine wearing an Australia flag-inspired dress, while Ash, who is in Los Angeles, shared a picture of herself with friends including fellow Aussie model Nicole Trunfio.Fitzy, who along with co-host Wippa hosted an Australia Day barbecue on Fort Denison, snapped a picture of himself with his two sons.Elsewhere on the FM radio dial, Kyle and Jackie O celebrated with novelty glasses and throwing some snags on the barbie. Sandilands' always-controversial girlfriend Imogen Anthony bizarrely uploaded an image of herself in a undies and a crop top emblazoned with the slogan "best buds" and a picture of marijuana leaves.