Singer Alexandra Burke has revealed she has dropped a dress size due to her “demanding” Strictly Come Dancing regime.

The former X Factor winner said she is now a “firm size eight” after just three weeks of the dancing competition.

Writing in the Radio Times, Burke said she was “aching all the time”.

“Strictly is definitely the most physically demanding thing I’ve ever done – and I’m used to going to the gym five or six times a week and performing at the theatre every night.”

She added: “I’ve also noticed that my body is changing and I’m losing weight – my Strictly costume had to be taken in last week.

“I’m now a firm size eight and my size 10 clothes don’t fit. That’s probably down to the relentless cardio workout of dancing as well as losing muscle because I’m not in the gym as much.”

Partnered with Gorka Marquez, the duo received the second-highest score from the judges in Saturday-night’s show after dancing an American Smooth to Wouldn’t It Be Loverly.

Burke said during rehearsal for the dance she would end up in fits of laughter because of the close nature of the dance.

She wrote: “Every time we ran it in rehearsal I kept getting quite giggly and embarrassed by being so close to him and pretending to be in love – we got to a point where we had to stop and he went red-faced, but then I started tickling him and we were laughing so hard we were crying.”