Prime Minister Kevin Rudd made the announcement this morning, with Mr Beazley long considered a favourite for the position.

He will replace Dennis Richardson, who is scheduled to come home in November to head the Department of Foreign Affairs and Trade.

VIDEO: Beazley goes to Washington

Mr Rudd also announced Brendan Nelson as ambassador to European Communities, Belgium and Luxembourg and Australia’s representative to NATO, the North Atlantic Treaty Organisation, and the World Health Organisation.

Mr Rudd said Dr Nelson had a distinguished record of public service and would serve Australia well.

Dr Nelson’s last day in Parliament is today.

Both Mr Beazley and Dr Nelson had served as defence ministers, both had led their parties and both had earned the trust and respect of the Australian people, Mr Rudd said.

Both Mr Beazley and Dr Nelson attended the announcement of their diplomatic appointments.

Mr Beazley described his appointment as "an enormous honour'', saying he could not think of a better thing to do at this time.

Mr Rudd defended the appointment of Mr Beazley and Dr Nelson over professional diplomats.

There was no-one better qualified in Australia to be the US ambassador than Mr Beazley, Mr Rudd said.

And the prime minister said Dr Nelson's experience as defence minister was important in the European role, especially the relationship with NATO.

- with Stephanie Peatling