With her much-discussed Grammy appearance and a new hit single, Gaga is suddenly everywhere again. Can the pop superstar top herself?

It is an unseasonably warm Grammy Sunday in Los Angeles, and the preshow red carpet is a spangled traffic jam of celebrity, the night’s nominated stars vamping for the cameras and tossing sound bites to a clamoring press. But the one woman the media most want to speak to isn’t talking at all — in fact, she’s hardly showing her face. Lady Gaga, pop music’s high priestess of life-as-performance-art, has made her entrance in a semi-opaque space pod, held stoically aloft by a team of vinyl-clad fashion gladiators. The only clear indication of the blurred figure inside the egg-shaped vessel is a single black-gloved hand, pressed demurely to its inner wall. She is here to perform ”Born This Way,” the lead single from her upcoming album of the same name, and to officially launch the next stage of a career already defined by the singularity of its meteoric rise. First, though, she will have to be hatched.

There was a time, of course, when the world carried on just fine without the contributions of the singer born Stefani Germanotta. But for the past two years, her domination of the pop culture conversation has been so complete that it can be hard to recall a zeitgeist that did not include her. Since the release of her debut, The Fame, in October 2008, and its EP semi-sequel The Fame Monster in November 2009, she has sold some 16.5 million albums worldwide and 29.5 million digital singles (seven of which cracked the top 10 of Billboard’s Hot 100). She’s also logged an astounding 1.2 billion music-video views online.

There is little arguing with her past success; now, with the 24-year-old’s third release, Born This Way, due May 23, comes the question of whether she can sustain it. Details of the album are closely guarded by her camp, though Vincent Herbert, the producer and label exec who signed her the same day she walked into his office at Interscope Records four years ago clad only, he recalls, in ”fishnet stockings, panties, a bra, and a blazer,” has no qualms calling it the best thing she’s ever done. ”She’s made her Thriller with this album,” he says. ”It’s unbelievable, just hit after hit.”

And while Herbert may be biased, so far he’s right — at least about the hit part. ”Born This Way” shattered radio-airplay records its first day out, and shot to No. 1 on iTunes in all 23 countries that carry the service. ”It just sounded like a one-listen record,” says Julie Pilat, assistant program director and music director at L.A.’s KIIS FM. ”The fans are being very vocal; they want as much of it as they can get.”

Artistically, the song has gotten a somewhat cooler response, with critics and even some fans deriding it as unduly derivative of Madonna’s 1989 empowerment anthem ”Express Yourself.” That reaction suggests a potential long-term problem for Gaga: living up to increasingly inflated expectations. When you’re known for outrageous stunts and gigantic hits, how do you keep topping yourself?

”Of course, the natural instinct is to wonder: Where does she take it from here?” says Madonna’s longtime publicist, Liz Rosenberg. ”She’s taken it pretty far on the fashion front and seems to be having fun with it…. The next step might be a nice pastel sweater set with pearls and sensible shoes. That would be really shocking.”

Anderson Cooper, who spent time with Gaga in London, Milan, and New York City while taping a 60 Minutes segment that aired before Sunday’s Grammys, believes she’s just doing what comes naturally to her. ”We’ve seen plenty of artists who’ve transformed themselves over time to maintain the public’s interest,” he says. ”But no one’s done it as often and with such concentration and dedication and flair. She’s transforming herself every few days, it seems. There’s a real discipline to her artistry — the discipline of never wanting to be seen in sweatpants and sneakers. I don’t know how she does it; I would think it’s exhausting. But with her, she will tell you, ‘Look, this is who I am.”’

There’s a discipline, too, to her pacing. Born was recorded while she continued to tour and promote her previous album, an increasingly common practice (Rihanna and Ke$ha also recently released CDs less than 12 months apart) in the era of what her manager Troy Carter calls ”the 24/7 media thing.” ”That’s the difference between being a superstar now and 20 years ago,” he says. ”You’ve got TMZ and the Huffington Post and the paparazzi.” That means no tabloid shots of Gaga in rumpled loungewear — perhaps because she never lounges. Unlike many of her pop-star peers, she is rarely seen lazing on tropically anchored yachts or schmoozing at industry events. Says Herbert: ”She gets her massages and she works out and she stays fit, but she loves to work. She was supposed to take three weeks off during the Christmas break, but she called me and Troy and was like, ‘Okay, it’s been four days, I’m ready to get back to the studio.”’

The best predictor of Gaga’s future may be the artist herself, who told EW in 2009: ”I’m not trying to prove to anybody that I’m going to be here for 30 years. You either are or you’re not. You either have passion for it or you don’t. It’s either important for you to stop and buy a condo and have babies and marry a rich actor, or not do any of that, and continue to make music and art, and die alone. Which is what I’ll probably do…. So it will be one continuous thought until I’m laying in a coffin, surrounded by all of my props.”

Additional reporting by Whitney Pastorek and Tim Stack