Bravo! The fatgirl slim opera singer who lost half her weight and became twice the woman

Then Deborah Voigt lost more than half her body weight and the Royal Opera House finally invited her back.

Last night, the 47-year-old American singer was at Covent Garden to perform the title role in Richard Strauss's opera, Ariadne auf Naxos, four years after she was originally scheduled to sing it.

A packed house cheered and clapped as the svelte  -  by opera standards  -  diva fitted more than elegantly into the little black dress deemed so crucial to the production.

Diet diva: Deborah Voigt at the Royal Opera House last night and in 2004, right

Voigt, who was 25 stone at her heaviest, dropped to 10 stone and went from size 30 to an average 14 after undergoing gastric bypass surgery following the ROH decision in 2004.

She said the weight loss was necessary for her health. 'I did it because I wasn't feeling well, because my knees were hurting, because I would cross the street and feel as though I wasn't going to be able to catch my breath,' she said.

But the decision proved controversial in opera where the fat diva is no joke.

Purists argue that it is the voice, not the appearance, that counts in what is arguably the art world's most elitist genre.

The argument sometimes stretches plausibility but means extra-size singers have been the norm for generations.

The career of Greek singer Maria Callas, arguably the world's most famous soprano, was deemed to have taken a downturn after mid-career weight loss turned her into a sexy star  -  although her heavy workload and inability to give anything but her all may have contributed to the vocal decline.

The audience last night obviously had no doubts over the impact of a diet on Voigt.

She held her own even though she was cast against a waif-like and engaging Gillian Keith as Zerbinetta, a scene-stealing role.

It was a triumphant return for Voigt who said she was 'as big as a house' for her last appearance at the ROH in 2001.

But in every sense she has had the last laugh.

Last week she posted a video spoof, 'Deborah Voigt  -  The Return of the Little Black Dress' on the internet.