On a springlike day in early March, Jennifer Lopez walked into the greenroom at the Today show. It was 7:30 a.m., and she mentioned that she was tired—as well she should have been. She’d arrived in New York from Los Angeles the morning before at 4 a.m.; slept for a few hours at her apartment just off Madison Square Park; gone to the cover shoot for this magazine, where she stayed until 8:30 p.m.; changed clothes and rushed to Il Mulino, an Italian restaurant in Greenwich Village to meet with L.A. Reid, the head of Epic Records, which she had just rejoined, after a six-year separation; changed clothes again and then, at 10:15 p.m., appeared on Bravo’s Watch What Happens Live, where she’d answered questions about her ex-fiancé Ben Affleck’s enormous tattoo (“Awful!”), and whether or not she uses handcuffs in the bedroom (“I think that question is too personal”).

But Lopez, who was dressed in a long-sleeve white lace minidress and black suede over-the-knee high-heel boots, appeared surprisingly fresh. “I’m exhausted just looking at all that you do,” Matt Lauer, the show’s host, said to her before their on-camera interview. He then left her and her seven-member team—including her wardrobe, hair, and makeup glam-squad, her manager, her producing partner, a publicist, and one very handsome bodyguard—in the small dressing room.

The Today show is, in fact, a labyrinth of sets scattered over different floors of a building in Rockefeller Plaza. Tina Fey and her entourage passed by on their way to do a segment, and a burly male chef in an apron stood in a corner. “Last night was kind of crazy—everyone was crushing on Anthony,” Lopez said, referring to her bodyguard, as she sat down on a couch. The Watch What ­Happens Live appearance had kicked off a three-day promotional blitz for Lopez’s exceptionally full roster of projects: the final season of American Idol, on which Lopez was a judge, was about to end; she has a three-year residency at the Planet Hollywood Resort & Casino in Las Vegas, where her extravaganza show resumes May 22; and Shades of Blue, a cop drama on NBC, of which Lopez is a producer and also the star, had just been picked up for a second season. All that, and yet the previous night, the main topic, as it often is with Lopez, had been her fabulous self. “Do you think the Kardashians stole your jam with having a great ass?” Andy Cohen, the host, asked on air. Lopez smiled. “I think I paved the way for them,” she said. “Just another innovation that I’ve given to the world!”

There’s a central dichotomy with Lopez: At 46, she’s both glamorous and endlessly industrious: a red-carpet star who convincingly portrays a single, blue-collar mom of a 16-year-old on TV. What’s more, her love affairs with powerful men as varied as Affleck, Sean “Puffy” Combs, and her ex-husband, the singer Marc Anthony, have all played out in public, making her seem at once formidable and approachable—a kind of people’s diva. “I’ve been in the grind and the game for a long time. At a certain point, people respect you when they see you fall down and get back up. The more you’re in this life, the more they celebrate your triumphs.” Lopez paused. “When it comes to work, I never get tired. But with personal failures, I have thought, This is too hard. When my marriage ended, it was not easy to find forgiveness. It wasn’t the dream that I had hoped for, and it would have been easier to fan the flames of resentment, disappointment, and anger. But Marc is the father of my children [8-year-old twins], and that’s never going away. So, I have to work to make things right. And that is, by far, the hardest work I do.”

It was time for Lopez’s interview, and her team walked onto an empty kitchen set to watch her on a monitor. Lauer, slim and elegant in a gray pinstripe suit, asked Lopez about her packed schedule. “And you look great,” he gushed. “Please tell me where you hide the time machine?!” He sighed. “I just want one hour with your time machine.”

Lopez, who does look remarkably young, smiled and demurred. Her famous derriere aside, she is petite and fine-boned. (“When I first came to Los Angeles, someone told me I would be a star because of my tiny ankles and wrists,” she later admitted. “They said that was the key to it all.”) Lauer persisted, fishing for the secret to Lopez’s stamina. “As a kid,” she said finally, “I would hear the grown-ups talking in the next room, and I wanted to find out what they were doing and then do it. I always had a fear of missing out.”

Lopez, who grew up in the Bronx, got her big break—when she was 22—as a Fly Girl dancing on the TV show In Living Color. She moved to L.A. and six years later was cast as the lead in a biopic about Selena Quintanilla Perez, the Tejano pop star who was murdered by the former head of her fan club. Selena was a box-office success, and Lopez became one of the first Latina actresses to cross over to a mainstream audience. She has always been conscious of her core Hispanic fan base, so that day her next stop on the interview circuit was Telemundo studios, across the street from the Today show.

That sounded easy enough, but Lopez cannot cross the street without creating instant mayhem. “Let’s go,” she said, wrapping a gray tweed coat with a fur collar tightly around her. Lopez walked swiftly, with her bodyguard at her side, but within seconds, a loud mob had gathered out of nowhere and was moving toward her. Lopez was polite, but she didn’t stop. The speed of the onslaught was unsettling. “It’s been like that since Selena,” Lopez said after she was safely inside her Telemundo dressing room. “I never thought about fame until then. After that film, I would have panic attacks. I remember walking down the street, and someone yelled, ‘Jennifer!’ and I didn’t know who it was. I ran home. From that point forward, I realized I couldn’t be alone in public. I don’t think I’ve been alone on the street in over 20 years.” Following the short Telemundo interviews, which were conducted in Spanish, everyone returned to the Today studio for a segment with Kathie Lee Gifford and Hoda Kotb. This time, Lopez made the short trip below street level, around the skating rink. She changed into a 1950s-style gray dress with a tight bodice and flared skirt. “Last time I was here, they asked me who is better in bed—dancers, musicians, or actors? I said, ‘Dancers!’ ” Lopez looked half-annoyed and half-amused. Casper Smart, her on-and-off boyfriend since 2011, is a dancer and actor. “Musicians are too self-absorbed. They are too concerned with themselves to be great in bed.” This might have been a dig at her ex-husband. He and Lopez were a golden couple in the Latino community. “I hung in there for seven years,” Lopez elaborated. “I knew very quickly that it wasn’t the right thing.” Smart has his own house but seems very devoted to Lopez and her kids. “We got together and broke up and are now together again. I still think about getting married and having that long life with someone. I love the movie The Notebook. A dream of mine is to grow old with someone.”

Lopez headed downstairs to the main Today set. In an effort to evoke her TV show, a bed had been made with sheets in shades of blue, and, further belaboring the tie-in, Lopez, Gifford, and Kotb were eating blueberries from a blue bowl. All three women sat on the bed (“We’re in bed with J. Lo!”) and asked tame questions submitted by fans via Facebook. “If you didn’t have your career, what would you do?” Kotb asked. “I would be a painter,” Lopez said. “I can’t paint. But I feel I could learn anything if I worked hard enough. Never say never!”

After a quick goodbye hug, Lopez and company headed to an underground garage, where two black SUVs waited to take them to the set of Wendy Williams’s syndicated talk show in Chelsea. Williams is a favorite of Lopez’s mother’s. “She watches her every day,” Lopez said as we made our way down Fifth Avenue. Williams used to be an outspoken radio personality, and her show, which is geared toward urban women and tries to be provocative, is not the usual stop for a star of Lopez’s stature. But the appearance is part of her mass attack, high/low strategy. This afternoon, she was scheduled to tape Late Night: Seth Meyers; it’s doubtful that the two audiences overlap. “We don’t want to leave anyone out,” Benny Medina, her manager, said.

Lopez’s look was a chic black openwork dress with a prim white collar and black pumps; her hair was pulled back into a bun. Williams wanted to talk only about her love life: “Last time you were on the show, you were totally single.” Watching from the dressing room, Lopez’s publicist was seething. “She’s supposed to ask about the show, about Vegas,” she hissed. Lopez, however, was in control: “Wow, Wendy—you really look great!” she said, deftly changing the subject. “You really have to come to my show in Vegas!”

By 1:30, Lopez was tucked into a booth in the café at Pier 59, a photo studio, and she was starving. She had ordered a mozzarella-and-prosciutto panini (no tomatoes!), but because she had a two o’clock appointment to visit a potential school for her kids, she would have to take the sandwich to go. I asked her if the nonstop pace ever felt overwhelming. “I do have trouble saying no,” she replied. “It’s hard for me not to imagine doing everything I am asked to do. Even if I hear a song that someone else has done or watch a film that someone else is in, I think, Oh, I would do it like this. Or, I wish I could do it like that. Luckily, I love to work.”

Since she joined American Idol, in 2011, Lopez has enjoyed a different relationship with the public. Her fans see her as more accessible, genuine, and likable. “It has been easier,” she said. “People may now think I’m ‘nice,’ but they still act surprised when I’m smart. It’s a man’s world, and, truly, people in a business setting do not value a woman as much as a man. I feel like I’m constantly having to prove myself. If a man does one thing well, people immediately say he’s a genius. Women have to do something remarkable over and over and over. And, even then, they get questions about their love life.” She shrugged. “People underestimate me. They always have, and maybe that’s for the best. It’s fun to prove them wrong.”

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