Madonna reportedly shocked fellow passengers on a recent transatlantic flight when she started injecting herself with vitamins instead of eating any food.

The singer, who turns 49 today, was travelling back to London from her recent trip to New York and was seen refusing offers of food during the journey.

An onlooker told Closer magazine: “Seven hours was a long time to go without eating. Madonna was quiet, talking to the air staff only to ask for bottled water.”

“Just before landing, she brought out the phials of vitamins and injected herself.”

The vitamins, believed to be B6 and B12, are said boost energy levels and have been used by the likes of Britney Spears and Geri Halliwell in the past to give them a boost before gigs. However nutritional experts claim they’re unnecessary and potentially dangerous for otherwise healthy individuals.