Australian police have charged a man with indecently assaulting American actress Sarah Hyland, star of hit television comedy Modern Family, in Sydney.

The cast of the ABC series arrived in the city this week to shoot an Australian episode.

The Sydney Morning Herald newspaper reported that the 23-year-old was attending a social function for cast members at a Sydney hotel when she was allegedly groped on the chest by a man who had asked her to pose for a photograph.

Hyland, who plays big-eyed teenager Haley Dunphy, immediately alerted private security guards, who called police to the scene.

Police said in a statement that a 29-year-old man had been charged following the alleged indecent assault.

Hyland later apologised on Twitter to fans for leaving early.