The Grease star was among the guests at a party in Beverly Hills to mark the annual G'day USA week, which celebrates Australians living and working in America.
Aussie stars including Liam Hemsworth, Miranda Kerr and Anthony LaPaglia also turned up for the bash at the Montage Hotel, and the highlight of the evening came during Urban's performance, when he asked Travolta to join him for a song.
The Hollywood actor, who is an ambassador for Australian airline Quantas, got up on stage with Urban to sing a duet of The Beatles classic Yesterday.
Urban also told the crowd that he and his actress wife Nicole Kidman take a lot of pride in their Australian connections, even though neither of them was born in the country: "It's a privilege to be able to lend my support to promoting the beauty and culture of Australia. There's a spirit about Australia that I see in our girls (the couple's two daughters), even though they were born in Nashville. Strangely enough, Nic was born in Hawaii and I was born in New Zealand. But we were fully raised in Australia - all our childhood memories are Aussie. So I can see there is a particular spirit in our house that the girls have without having been raised there."
Supermodel Kerr, who has a son called Flynn with British actor Orlando Bloom, also told reporters her little boy is aware of his Australian roots, saying, "He does love (Australian food paste) Vegemite on toast, and I've taught him to say, 'G'day mate' and he puts his thumb up too. Australia is such a special place and I'm really proud to be Australian."
The G'day USA celebrations include a lavish gala in L.A. on Saturday night (12Jan13) which will feature an awards presentation honouring Crocodile Dundee star Paul Hogan, actress Rose Byrne and Travolta.