Keen to help, Madge arrived on the East London set and invited the actors to her Range Rover, where she delivered vitamin B12 jabs.
Actor Tom Hardy, who plays Handsome Bob in the gangster movie, said that he was shocked when he spotted Madonna administering injections to the bottom of fellow actor Gerard Butler.
"I knew it would be magnificent to meet her because she's cult - I mean like Elvis - but the last thing I expected to see was her giving Gerard a shot in his back because he wasn't very well," Contactmusic quoted Hardy, as telling the Mirror.
"She was so cool. She just said to Gerard, 'there you go - bosh! That does it," he added.