She has refused to comment on plastic surgery speculation over the years.

But Delta Goodrem came under scrutiny yet again on Sunday, when viewers accused The Voice coach of undergoing ‘cosmetic work’ after seeing her on launch night. 

Fans flocked to Twitter to claim that the 34-year-old singer has had ‘too much work’ done to her face, with one person observing she has a fuller top lip. 

‘What’s happened to her face?’ The Voice fans have accused Delta Goodrem, 34, of getting cosmetic work after she displayed a very polish appearance on launch night. Pictured left: on The Voice, and right: in 2007

‘Delta has had more work done. Can’t work it out… she doesn’t need to do anything she’s beautiful!’ another added. 

‘Top lip? Was thinking that,’ wrote a third eagle-eyed fan, before somebody else asked: ‘What happened to Delta’s face? #toomuchworknow.’

Speculation: Bewildered fans flocked to Twitter after Sunday’s episode of The Voice to claim that Delta ‘has had more work done’

It’s not the first time Delta has sparked cosmetic surgery speculation. 

Last year, a leading plastic surgeon speculated that the Born To Try hitmaker may have invested in some cosmetic tweaks over the years.

Dr. Randal Haworth told Daily Mail Australia he had a ‘strong hunch’ Delta may have undergone a rhinoplasty, as well as cheek and lip fillers.

Claims: Last year, a leading plastic surgeon claimed that Delta may have undergone a nose job in addition to cheek and lip fillers. Pictured left: on The Voice, and right: in April 2003

‘Certain angles may be more revealing than others, but I have a strong hunch she has undergone a rhinoplasty because the shape of her tip is more demarcated from the rest of her nose while her bridge is noticeably narrowed,’ he said at the time.

‘These are the types of characteristics that would make any plastic surgeon suspicious,’ he added. 

Dr. Haworth also believes the songstress may have indulged in some other non-surgical cosmetic procedures.

Hmm! ‘I find it apparent that both her cheekbones and her lips have been enhanced with a temporary filler,’ Dr. Randal Haworth said. Pictured left: on The Voice, and right: in 2003

He claimed Delta’s full cheeks and plump pout could be the result of temporary filler.

‘I find it apparent that both her cheekbones and her lips have been enhanced with a temporary filler, most likely of a hyaluronic acid variety such as Juvéderm or Restylane,’ he said.

‘Celebrities with busy schedules oftentimes can’t afford the recovery time needed to undergo fat transfer for more permanent results,’ he explained.

Daily Mail Australia has contacted Delta Goodrem’s management for comment. 

Could it be? Delta sparked speculation with her plump lips and incredibly smooth complexion