Madonna was forced to digitally cover up a topless pal after falling foul of snap-sharing website Instagram's bare-breasted nipple ban while posting shots from her 56th birthday on Sunday (17Aug14). The pop superstar celebrated with a 1920s-themed bash at a villa in Cannes, France and uploaded photos of her hanging out with friends like Guy Oseary and Kate Moss - but one saucy shot featuring Madonna posing with a topless pal landed her in trouble. Instagram bosses swiftly removed the nipple picture, forcing Madonna to post it again, this time with the woman's nipples covered. She added the caption, "Instagram can take away our nipples but they cant (sic) take away our fun!" The singer also posted a vintage topless pic of herself on Instagram, but she escaped upsetting website chiefs because her nipple was blocked by a glowing light. Madonna may also have upset her ex-husband Guy Ritchie by posting a shot of their son Rocco from the party and joking, "Jeff Spicoli is alive and well in the South of France", suggesting the teenager looks like her first husband Sean Penn, who portrayed Spicoli in Fast Times at Ridgemont High.