She's just been voted the most powerful celebrity in the world, yet lasting happiness has proved elusive for Jennifer ...

PUBLISHED: 17:24 EST, 19 October 2012 | UPDATED: 17:24 EST, 19 October 2012

During nearly two decades in the spotlight, she has adopted many personas.

She was plain Jennifer Lopez for the film that put her on the Hollywood map, 1998s Out Of Sight with George Clooney, before her foray into rap with 2002 song Jenny From The Block, which gave her her first nickname.

Then she morphed into J-Lo with the album of the same name, which was followed by Bennifer, the nickname given to her and actor Ben Affleck while they were a couple.

Jennifer Lopez is currently on the European leg of a gruelling 48-date world tour, which comes to London on Monday

Most recently, by virtue of her marriage to one of Latin musics biggest stars, Marc Anthony, shes been Jennifer Lopez Anthony, the first lady of modern Latin pop.

But now, at 43, theres too much going on in Jennifers life to boil her down to a simple soubriquet: three-times-divorced actress, singer, dancer and doting mother of four-year-old twins, Emme and Max, shes been named the worlds most powerful celebrity of 2012 by the influential Forbes magazine, trumping Oprah Winfrey and Lady Gaga.

She has a lucrative line of 18 fragrances, an endorsement deal with LOral, a clothing range, not to mention her 10 million followers on Twitter and 14 million Facebook fans.

Shes currently on the European leg of a gruelling 48-date world tour, which comes to London ! on Monday.

When we meet, before her opening show in Lisbon earlier this month, she tells me, I might seem a lot of different things to different people, but the truth is Ive never changed. When I first started out, people were very quick to dismiss me as just a singer or an actress and then over time, as you keep working, little by little you gain respect. Of course, I live in a bigger house than the one I was brought up in [in New Yorks tough Bronx district], but I still have the same values and traditions, and live pretty much the same as when I was growing up.

She refuses to employ professional nannies, instead relying on mother Guadaloupe, cousin Tiana and her best friend from childhood, Arlene, to help with childcare.

Breaking up with Anthony was one of the most difficult things she says

My whole familys still there with me. We go everywhere together. Yet she admits, because of her wealth, she has a trickier time than her own parents keeping her children grounded.

I have to show my kids even more through example that hard work and being loving and giving really matters in being a good human being.

Guadaloupe was a kindergarten teacher and Jennifers father, David, a computer technician. She has an opera-singing elder sister, Leslie, and a younger sister, Lynda, who is a radio journalist, and credits her parents with instilling in her an irrepressible drive. I was always ambitious. I wanted to accomplish things. My dad worked nights and my mum worked during the day. I just took this way of life on board.

Of all Jennifers roles, it is clearly motherhood she takes the most seriously. Being a mother does change you. For example, I wouldnt do a crazy love scene in a movie now.

Yet she hasnt allowed her maternal instincts to c! ramp her ! style. Would she still wear that daring, slashed-to-the-navel Versace dress that caused a sensation at the Grammys in 2000? You bet! I still dress the way I dressed before, she says defiantly. I dress how I feel.

Emme, she reveals, has inherited her love of clothes. From the time she was little she was always in the wardrobe trying something on. So recently, when I was invited to the Chanel fashion show in Paris, I thought it would be nice to take her with me.

But she concedes it was a mistake. Emme was decked out in 1,500 worth of Chanel jewellery, and the sight of a glammed-up Jennifer Lopez and bling-festooned daughter was enough to start a stampede.

I hadnt been to a fashion show for ages and I forgot people could rush you. They were so close and I got so full of anxiety, thinking, What am I doing here with my daughter? But she was fine. I was the one freaking out. I dont think Ill do that again.

Jennifer poses with Randy Jackson, Ryan Seacrest, and Steven Tyler on American Idol, she is now one of Forbes list's most powerful women

The last two years, she says, have been tough. Its because of her resolve to end her seven-year marriage to five-time Grammy award-winning singer Marc Anthony last year reportedly because of his infidelity, though shes never publicly confirmed this and the subsequent divorce.

It was one of the most difficult decisions Ive ever made, she says, as her eyes fill with tears. Its been tough and my life has had to involve a lot of manoeuvring.

It was her third marriage. Her first, pre-celebrity, to Cuban waiter Ojani Noa in 1997 lasted 11 months. This was followed by a tempestuous two-year liaison with rapper Sean P-Diddy Combs. After that,! she soug! ht refuge in a ten-month marriage to backing dancer Cris Judd in 2001.

And then Bennifer her two-year union with Affleck took interest in her to new levels of hysteria, thus contributing to them calling off their engagement in 2004, leaving her devastated. This led to her surprise wedding just months later to Marc Anthony. Following their divorce, she has been with 25-year-old choreographer Casper Smart for the past 11 months.

'My whole family's still there with me. We go everywhere together'

Recently the pair denied rumours of an engagement when Jennifer was seen sporting a dazzling diamond ring. Were taking it day by day, she says. You learn certain things through your experiences and you have to ask yourself, Do I like this person? Do I trust this person? She merely says her relationship with Casper is nice and works right now a far cry from her protestations of passion for her previous beaux. Shes a woman who admits shes in love with love.

She maintains the failure of her third marriage hasnt made her cynical about relationships. You cant colour the whole world because of your bad experiences, she says.

Im not going to brand every person as untrustworthy. You have to believe theres somebody out there who is trustworthy, wholl stick in there. Inevitably, she still feels raw from the trauma of the divorce from Anthony.

Its difficult when a family breaks up, she sighs. Im still living through it, just trying to do my best with the kids and moving on. But, she adds, I still believe in love. That would be my message: love is the most important thing.

I sense it is her failed relationship with Affleck shes referring to when I ask her about her biggest mistake. I feel it was not giving certain things chances, she says. As in a certain r! elationsh! ip? Maybe, she replies coyly, adding, Im not talking about what just happened [the divorce from Anthony], but something in the past.

But brooding over what might have been is not in the Lopez DNA. Two years ago, after taking a short break to have the twins, she set out to revive her career. She recorded a hit comeback single, On The Floor, and signed up to a 7.5 million salary as a judge on American Idol.

She burst onto the scene as 'Jenny from the block' but has evolved into a style queen

However, after two triumphant series, Jennifer called a halt. When I started on American Idol, I cant tell you how many people told me not to do it, but in my gut I knew I should. In the end, though, I just thought to myself, do I really want this?

'I wanted to get back to what I do, which is sing, act and dance. But when I ask her what she considers her greatest talent, she says, Im good at being a mum. Though Im like most mums we beat ourselves up, so we never feel like were perfect.

At this point, Emme runs in and plants herself on her mothers lap. Jennifer covers her with kisses. Its clear shes in a good place, and ready for more good things to happen. When I finish the tour I want to come out better than when I started. Thats my goal for all experiences that are supposed to be hard. Ill come through this better and not let it take a toll on me.

Jennifer Lopezs first ever UK arena show is at Londons O2 on Monday.