The Australian band Men at Work are facing a big legal bill after a court ruled it had plagiarised a Girl Guides' song in its 1983 hit, Down Under.
Larrikin Music had claimed the flute riff was stolen from Kookaburra Sits in the Old Gum Tree, written by Marion Sinclair in 1934.
The federal court in Sydney ordered compensation to be paid.
That amount has yet to be determined but Larrikin's lawyer said it could reach 60% of income from the song.
"It's a big win for the underdog," said Larrikin's lawyer Adam Simpson after the judgment.
Sinclair, who died in 1988, wrote the song for performance at a Girl Guides Jamboree in 1935.
Kookaburra Sits in the Old Gum Tree has since been sung by generations of Australian schoolchildren.
A costs hearing will take place in late February, with Larrikin seeking 40%-60% of earnings from songwriters Colin Hay and Ron Strykert and record companies Sony BMG Music Entertainment and EMI Songs Australia.
Down Under, first released in 1983, was used in the closing ceremony of the Sydney Olympics in 2000.
A number one in Australia, the US and the UK, the song tells the story of an Australian backpacker touring the world.
It pays tribute to "a land down under where beer does flow and men chunder".
The song also refers to the popular Australian food spread Vegemite.
"I said 'Do you speak my language?', he just smiled and gave me a Vegemite sandwich," says an Australian traveller in Brussels.