Lily Allen hired top fitness guru to help trim down

Fitness guru: David Marshall

On top of this, she has to drink a special juice of ginger, beetroot, carrot, apple and celery, as well as concentrated artichoke and celery juice tonics three times a day.

Marshall - who can also boast Ant and Dec, Frank Lampard and Rio Ferdinand among his clients - is not known for mincing his words, and his training sessions with feisty Lily often turn the air blue.

"She is very conscious about how her figure is portrayed in the media, and is paranoid about her chunky bottom half."

"It was her new management team that recommended David, and they were keen for her to get back into shape. She has been working out every other day, with particularly gruelling exercises to get rid of her 'cankles' where her calves join her ankles."

"David makes her do controlled weight training, doing 25 reps with a heavy weight. It's pretty agonising, but Lily keeps coming back for more. She is four weeks into her six-week course, and has already dropped two dress sizes."