Have age and stress launched a shocking attack on Madonna's face?

But bare-faced and in short sleeves, she reveals some of the gruelling health and beauty regime behind the glamour.

Madonna, seen holding hands with her daughter Lourdes as they left a Kabbalah centre in New York, wore a T-shirt which exposed the veins standing out on arms subjected to endless workouts.

The singer's arms appeared too big for her gaunt frame as she arrived at a Kabbalah meeting, with popping veins and muscles as startling proof that her workout regime may be too much

Facing facts: Has time finally caught up with Madonna? She arrived at a Kabbalah meeting last week, left, looking less than her normal radiant self

Her swollen face renewed speculation that she is relying on more than yoga, the gym and a macrobiotic diet to ward off the effects of ageing.

She has remained enigmatic on the subject of cosmetic surgery, saying: 'I am certainly not against plastic surgery; however, I am absolutely against having to discuss it.'

Harley Street plastic surgeon Angelica Kavouni said: 'In my opinion, it is likely she has had filler in her cheeks because they are so full. There is no loose skin at the jawline which is also extremely unusual for someone her age. Typically, that is something we achieve through a lower facelift.

Grim faced: Madonna cuts a sullen figure as she leaves the religious centre with daughter Lourdes

Kicking back: The singer donned a pair of high heel trainers as she walked the New York streets

Nor does she have any loose skin around her eyes, which again is unusual.

'She always had nice eyes and high cheekbones, so if anything has been done I think she's trying to enhance her existing good parts and had some areas tightened.'

Madonna is 50 on August 16. Earlier this year a member of her circle told the Daily Mail: 'She's been having work done since her 30s, but in the past year she's really stepped it up, which is worrying.'