By now, even the most gentle readers among you probably have heard of Lady Gaga, stage name of the 24-year-old New Yorker Stefani Germanotta. In the past 18 months, she has sold an astonishing 12 million albums worldwide (no mean feat in these days of declining record sales), become the darling of both the broadsheets and the tabloids, and has just added yet another British date to her Monster Ball tour.

This week, she played two nights at London's O2 Arena. I went to see what is it about Gaga that attracts her Little Monsters -- the provocative, colourfully clobbered young fans that worship at her altar -- as well as the audience of conventional rock fans, and mothers and daughters, that make up her shows.

At the end of evening, I had a theory. At the same time as Gaga manages to shock and provoke people with her outlandish behaviour, she simultaneously cossets and welcomes the people who follow her. Also, unlike Madonna, the pop predecessor to whom she is always compared, she tells her audience to be themselves -- and that peculiarness is part of who we really are.

Her live show, for example, addresses mortality (which has suddenly taken on deeper resonance this week since rumours surfaced about her being diagnosed with lupus). There is one striking routine in which Gaga's dancers tear at her body, leaving her neck and chest covered in blood, which she doesn't remove. She also stops stock-still after songs for 20 seconds at a time, breathing heavily, as if issuing a death rattle.

Stage oddity

Even in her skimpiest outfits, Gaga foregrounds ugliness rather than prettiness, which shows us that her presentation is nothing to do with sexiness, and everything to do with the acceptance of weirdness. Among contemporaries of hers like Christina Aguilera and Beyoncé, as well as Madonna, this is unique.

Then there is Gaga's personal way of talking to her fans on stage. She talks at length about what their love for her means to her, her speeches sounding born of a hunger for friendship and acceptance, rather than a desire for dollar bills. She also tells her fans things they want to hear, but far too few pop stars tell them.

"You don't need money or plastic surgery to be a star," she says. "Reject the idea of not being good enough, thin enough, blonde enough. Like every motherfucker told me."

Whether they are straight or gay, black or white, anarchic or everyday, she tells her fans constantly to accept their odd qualities.

At the Monster Ball, Gaga says, everyone can be free.

There are other things that make Lady Gaga a great pop star, that people of all ages and backgrounds can see. There are her musical talents: the piano-playing with her fingers as well as her stiletto boots; the way she can make her voice growl and soar as well as soothe.

And there are songs like "Bad Romance", the set's dazzling encore. A five-minute epic that exposes the agonies of lust, and culminates in the most melancholic vocal in the pop canon for years -- "I don't want to be friends", she wails, desperately hinting at those times in our lives when we have all craved the opposite -- it reveals the high, dark drama in our real worlds. This is what Lady Gaga is all about. Long may we all be her monsters.