Daily Telegraph editor at large John Lehmann reports Kerr agreed to take part in the duet on the condition the single would be dumped if she didn’t like the finished product.

“It’s just a bit of fun,’’ said Kerr, who sang on a Japanese iced tea commercial in 2012.

“They approached me and I said, ‘I’m not a singer’,” Kerr said. “But they said, “We know, but you sang on that commercial’.

"I said, ‘If I don’t like it, it’s definitely not going anywhere’ — and they said, ‘Of course’.”

The video, shot in New York in October, will be shown for the first time on Channel Seven’s Sunday Night on May 4.

Fox admits he thought there was “no way” Kerr would agree to sing, though she dabbled in music years ago when she dated musician Jay Lyon.

“When they came back that she was interested in doing this specific tune, I f … ing passed out — I just thought, ‘Great’,’’ the Irish-born theatre star said.

“She has a lovely voice, and I’d love for people to hear it.”