Australia have chosen to play their opening match of the Ashes tour against Sussex, which starts on 24 June, in the 12-a-side format.
It gives the tourists a chance to give more players match practice, following a similar gesture made to England on their Ashes tour of 2006/07.
Australia captain Ricky Ponting said: "We will be going all out for an emphatic performance at Hove.
"This will provide invaluable preparation for an additional player."
Sussex cricket manager Mark Robinson said: ""We are delighted to be hosting the opening match of the Ashes Tour.
"Whilst ideally we would have liked the game to have been played 11-a-side, the 12-a-side participation will mean that the Sussex public will see more of the major Australian players."
"We will be fielding the strongest possible Sussex side to test the Australian team in this important warm-up fixture."