Nick Kyrgios' big sister Halimah to shine on The Voice Australia

Ads for Sunday's show seem to reveal Guy Sebastian pressing his buzzer during Halimah's performance but her brother Christos, the oldest Kyriogos' sibling, who was there on-set, says Sebastian was not the only one.

"I can tell you more than one turns around," he said.

Christos was watching Hali's performance in the wings of The Voice stage with his fiance Alicia.

Brother Nick and their parents Norlaila and Giorgos also joined via video call from Canberra as Hali performed Tina Arena's showstopper Chains. Host Sonia Kruger said after the performance: "She was amazing!" Nick replies: "She always is."

Christos said seeing his sister sing live was "incredible". "I know it sounds cliched, but hearing her sing always gives me goosebumps and I get a little bit teary," he said.

Halimah, whose partner is Nick's manager Daniel Horsfall, went to school in Canberra at Rosary Primary School in Watson and Radford College in Bruce. She has in more recent years been performing in musical theatre overseas.

Christos said he was thrilled to see his 31-year-old sister get her time to shine.

"100 per cent," he said. "She works just as hard as anyone else out there.

"I guess, similar to Nick, to do what they do takes a lot of dedication and a lot of time away from home and family. So many of my memories of my sister are of her being overseas and performing in different musicals around the world. It does make me so happy to see her have her moment in the spotlight."

Christos says there was a restriction on how many people could attend Hali's performance with her partner Daniel waiting on tenterhooks at a nearby hotel to find out the result.

He said fans of the show who already found the performances emotional, would be really getting out the tissues on Sunday night.

And it remains to be seen which judge Hali teams up with - Guy Sebastian, Keith Urban, Jessica Mauboy or Rita Ora.

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