Diminutive in stature yet larger-than-life in character and emotion, Gaga has shot to the very top of her industry, a global music phenomenon whose debut album The Fame appeared in 2008 and went on to sell over 12 million copies.

It helped make her the world's most famous singer and arguably its biggest celebrity, with a little help from a series of outlandish outfits that have included a raw meat dress and turning up to the Grammy Awards in a giant egg.

She breezed into the offices of the international free newspaper network Metro and warmly shook hands with the staff, helping to relieve the tension that had been building up during the long wait for her arrival.

Watched by a small entourage of a record label representatives, make up artists, a PA and security guards, Gaga led the morning editorial meeting where she took immediate control and dominated proceedings throughout.

The lengthy session involved discussions about the Japan earthquake, transgender issues and bullying, and was punctuated by what may soon come to be known as "Gagaisms."

"Know that you are a part of the mobilization of love in the world," she said in the context of a chat about bullying.