The voice of Siri to perform at State of Origin

Karen Jacobsen (supplied)
Karen Jacobsen (supplied)

Siri will perform the Australian national anthem at tonight's rugby league State of Origin match.

But don't expect to see an iPhone held up to a microphone -- instead it'll be Karen Jacobsen, the voice of Australia's Siri.

Channel Nine's The Today Show showed a sneak preview of how the real Siri sounds when she sings.

Jacobsen, born in Queensland, is now based in New York. Her voice can also be heard on GPS units, voice-operated telephone systems and commercials.

Unlike her American voice counterpart, Jacobsen knew she was going to be the voice of Siri. Susan Bennett, whom Americans hear when they fire up Apple's voice assistant, only found out when a friend of hers told her.

"The recordings were done for a text-to-speech company starting in 2005," Bennett told comedy site Cracked earlier this year.

"Apple got all their Siri voices from this company, but they came in after the fact. We had no contracts with Apple."

Jacobsen told morning show Sunrise in 2013 it took 50 hours to record all the sounds needed for the Australian Siri.

"They provide a phone book worth of script, and they want to capture every combination of syllables possible so they can chop it up," she said.

Queensland currently lead New South Wales 1-0 in the annual State of Origin series, after a nail-biting 6-4 win in the first game.