Sia lost her voice while performing at Jennifer Aniston’s wedding

SIA says her performance at pal Jennifer Aniston’s secret wedding earlier this year wasn’t her best. In fact, she says it was ‘laughable’.

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SIA has revealed her voice cracked when she performed her hit songs “Chandelier” and “Titanium” in front of some big name stars.

The Adelaide-born singer described her performance at Jennifer Aniston and Justin Theroux’s wedding in August as “laughable”.

“I went for the ‘Chandelier’ chorus and it was like, it was actually hilarious. It sounded like three weird squeaky notes at the same time were coming out, it ruined the entire chorus,” Sia told Nova 969’s Fitzy & Wippa.

She also revealed she couldn’t hit the high notes in front of US President Barack Obama at the Democratic National Committee’s LGBT Gala in 2014.

“I think I did three songs and I think the end was ‘Titanium’ and I just couldn’t even hit that high note by the end, it was hilarious,” she said.

“That was for real, I opened my mouth and a squeak came out,” she said.

The Los Angeles-based singer also made a “controversial” and slightly un-Australian revelation.

“I am going to probably offend and insult most Vegemite lovers by saying I’m a Promite person. Controversial!” she said.

“If there is no Promite, I’ll eat it [Vegemite] and I’ll love it. But if there is Promite and Vegemite I’m gonna choose Promite every time because I love it.”