Up to 20,000 people - and possibly Skywhale - will gather at Government House next month for what is tipped to be the biggest event held at the Canberra landmark.
And all Canberrans are invited.
The Governor-General's Centenary Family Picnic Day will be held in the lush grounds of Government House on September 21 to help celebrate the national capital's 100th birthday.
Children from Giralang Primary School and Indooroopilly State School tested picnic rugs with Governor-General Quentin Bryce and Chief Minister Katy Gallagher on Thursday to promote the event, with the G-G warmly welcoming the students with ''would you like a biscuit?''
The children from Indooroopilly in Queensland were on their annual trip to Canberra and the school was once attended by the Governor-General's own grandchildren.
Ms Bryce said she and her husband Michael were looking forward to welcoming Canberrans and interstate guests to the grounds of Government House ''which belong to all Australians''.
''There's always a sense of excitement when families and friends visit Government House,'' she said.
''It's exhilarating for me to hear the sounds of little ones running up and down the corridors of this great Australian house. I like to meet with as many people as I can and to listen and learn from their stories.
''This will be the largest event ever held at Government House and I hope as many people as possible take the opportunity to enjoy the festivities.''
Families are encouraged to bring a picnic and blanket and enjoy live music, sports workshops, a petting zoo, reptile display, magic and street performers and a vintage car display. There will also be stalls in a market square, with 10 per cent of all takings going to the centenary's official charity Dollars for Dili.
Spring was a special time at Government House, said Ms Bryce.
''The gardens at Government House look beautiful at this time of year, and I know our gardening team is working hard to make sure it is in tip top shape for everyone to enjoy. ''Walking around the grounds of this historic property, I enjoy many moments of quiet reflection and inspiration.
''I look forward to seeing thousands of visitors laying out picnic rugs and baskets on the lawn and enjoying the many events and entertainment that are planned for the day.''
The Skywhale hot air balloon will also be back in Canberra skies in September and there is a possibility it will visit the picnic day.
''I think the Skywhale is a wonderful focal point for Canberra's centenary celebrations,'' Ms Bryce said.
Ms Gallagher said it was still to be determined if Skywhale would be available to visit Government House on the day.
- The Governor-General's Centenary Family Picnic Day will run from 10am to 4pm on Saturday, September 21. Entry is free.