JENNIFER Lopez rocked the house when she performed on stage with her man at this year's American Music Awards (AMA).

And no, it wasn't Marc Anthony.

The US actress-singer's former husband may have looked spiffy as he gyrated to Rain Over Me with sexy female dancers at the awards show, which was telecast from the Nokia Theatre in Los Angeles yesterday.

But the man she was steaming up the place with was her back-up dancer and new beau, Casper Smart.

This is the first time that Lopez, 42, and Smart, 24, have appeared together on a public platform, since news of their budding romance broke more than a week ago.

Lopez started her performance of her hit Papi by pretending to forget the words. Her voice cracked and she looked down. Then she suddenly threw off her cape to reveal a gold bustier and a naughty grin.

She later launched into another of her hits, On The Floor, with Smart - who sports a shaven head and tattoos on his right arm - dancing near her ample behind in one segment.

Lopez also thrilled the audience in her glow-in-the-dark costume while performing with will.i.am on his new single, T.H.E (The Hardest Ever).

And she beat Anthony to win Favourite Artist in the Latin music category.

In her acceptance speech, Lopez said: "I'm grateful for my blessings; I want to thank my family, my beautiful babies and my creative soulmate (referring to her music producer/manager Benny Medina)."

According to the Daily Mirror, Lopez and Smart, who reportedly met six months ago, have been dating for a few weeks.

And get this - it's "just about sex".

The 18-year age gap doesn't seem to be bothering Lopez, as a source was quoted as saying: "It's just about sex - and no one's sure if it has much of a future. "But he's (Smart) having a good time finding out."

Lopez's friends have reportedly confirmed that the pair are simply having a "fun fling" as Lopez has found Smart's charms "hard to resist".

A friend of Smart's was quoted as saying: "He said she's got the body of a 20-year-old. They're inseparable right now."

Lopez - who has two-year-old twins Emme and Max with Anthony - split with the US crooner four months ago after seven years of marriage.

Lap dance

In May, Smart shared the stage with Lopez during a performance on reality TV singing show American Idol, where she was judge.

The couple have been photographed having fun together in the last few weeks and have been seen partying in Las Vegas.

A source told Us Weekly that the pair got frisky at Pure nightclub and Smart had given Lopez a lap dance.

Entertainment news website TMZ was the first to release a picture of them posing together following Lopez's performance in Ukraine in July.

But even if there is a serious relationship on the horizon, Lopez is playing coy.

When asked by American Idol host and deejay Ryan Seacrest last week about the dancer she's been "hanging out with", Lopez sidestepped the question.

She said: "Until I'm in a really serious relationship (because of the babies), I'm not really going to be commenting on my personal life."

So who exactly is Smart?

According to Us Weekly, he's an Anaheim, California, native and dances at Club Boulevard in Los Angeles.

He is said to be especially popular with the ladies as he "goes shirtless" at the clubs.

The 1.73m-tall hunk performed with Beyonce at last year's Grammy Awards and has starred in dance flicks such as Honey 2 and Step Up 3D.

If all this sounds a tad familiar, that's because Lopez seems to have a penchant for her back-up dancers.

She met dancer Cris Judd on the set of her Love Don't Cost A Thing video and married him in 2001, though for less than a year.

Lopez may have stolen the show visually with her sizzling hot dance moves, daring outfits and her latest toyboy, but it was country music princess Taylor Swift who emerged queen of the AMA.

The 21-year-old snagged the top honour, Artist Of The Year, for the second time. She also bagged the Favourite Album and Favourite Female Artist awards for the country music category.

Another fan favourite was Canadian teen idol Justin Bieber, who drove the audience wild with his rendition of Under The Mistletoe. It didn't matter that his voice wavered and he was off-pitch for most of the song; he could do no wrong.

Bieber broke many hearts as he was seen looking lovingly at his girlfriend, Disney star Selena Gomez, who sat next to him in the audience after his performance. The couple looked visibly less strained since their last public outing at the 2011 MTV Europe Music Awards earlier this month.

Perhaps it's because since then, a paternity lawsuit against Bieber has allegedly been dropped by single mum Mariah Yeater, who had earlier controversially claimed that Bieber was the father of her son.

According to E! News, Bieber's publicist said he still plans to go ahead with a DNA test to hold "those involved with bringing this suit accountable for their actions".

Main list of winners

Artist of the year: Taylor Swift

Pop or rock music category:

Favourite Male Artist: Bruno Mars

Favourite Female Artist: Adele

Favourite Band, Duo or Group: Maroon 5

Favourite Album: Adele - 21

Country music category

Favourite Male Artist: Blake Shelton

Favourite Female Artist: Taylor Swift

Favourite Album: Taylor Swift - Speak Now

Favourite Band, Duo or Group: Lady Antebellum

Rap/Hip-hop music category:

Favourite Artist: Nicki Minaj

Favourite Album: Nicki Minaj - Pink Friday

Soul/Rhythm & blues music category:

Favourite Male Artist: Usher

Favourite Female Artist: Beyonce

Favourite Album: Rihanna - Loud

Sprint new artist of the year: Hot Chelle Rae

Latin music category

Favourite Artist: Jennifer Lopez

This article was first published in The New Paper.