Robbie Williams has gone on a juice diet.

The 41-year-old singer has stripped back his eating regime to just fruit drinks and freshly squeezed vegetables in order to shift some weight after piling on the pounds during his two-month break from his 'Let Me Entertain You' world tour.

A source told the Daily Mirror newspaper: ''Robbie's found it harder to keep the pounds off and maintain his body since giving up smoking a couple of years ago, so he has to work harder in the weeks leading up to performing if he wants to be able to look and perform at his best.''

The insider added: ''When he's not on stage, he does less exercise, eats more of his favourite foods like cake and crisps, and takes a little less care of himself diet-wise.

''He's been on juice diets before and tried protein shakes, and they seem to work best for him.''

But he isn't just relying on adjustments to his diet to beat the bulge as the 'Candy' hitmaker has also been training at the gym to ensure he's not branded ''the fat dancer from Take That'' when the Australian leg of his tour kicks off next week.

The source explained: ''He's been hitting the gym, doing weights and should be in good shape by the time he hits the stage in Australia.''

Meanwhile, the former Take That star and wife Ayda, who have children Teddy, three, and 11-month-old Charlton together, were left ''heartbroken'' earlier this week over the death of their pet pooch Spencer.