Casper Smart

Just how serious are things getting between Jennifer Lopez and Casper Smart? The pair vacationed together this week in Hawaii... along with J. Lo's three-year old twins!

The 24-year old backup dancer was "great" with the children, an insider tells Us Weekly, detailing how he "was twirling them around and doing flips with Emme and she seemed very comfortable with him," while "Jennifer got a chance to sit back and relax while Casper took over and played."

Lopez came under pretty heavy fire this week by shilling so hard for Fiat during her American Music Awards that even Kim Kardashian referred to it "too much." Okay, not really. But John Legend called out his fellow artist.

But Jennifer's personal life is going a lot smoother. Following the AMAs, witnesses spotted Lopez "grinding in Smart's lap, giving him a kiss and rubbing his head" at Greystone Manor in West Hollywood. He's a lucky fella.

Jennifer Lopez is reportedly still getting it on with Marc Anthony on occasion, but numerous sources confirm there's definitely something going on with backup dancer Casper Smart.

"It's pretty serious," an insider tells E! News. "They're together a lot. She couldn't be happier."

So, who the heck is Casper Smart? He's a 24-year old whose real first name is Beau. He's good friends with Mark Salling and has made cameos on Glee. In 2008, meanwhile, he also played a role in a Barack Obama/John McCain dance-off video, one that has garnered over 12 million YouTube hits. Yes, that is McCain's head superimposed over Smart's body below. Watch now.

Casper Smart as John McCain

Sorry, Bradley Cooper. According to a new tabloid report, your wooing has failed.

Us Weekly claims Jennifer Lopez has moved on fro Marc Anthony - and Cooper, apparently, who she was rumored to be flinging - via a relationship with Casper Smart, a dancer at Club Boulevard in Los Angeles.

"[He's] popular with the ladies because he goes shirtless!" a source gushes to the magazine.

Smart has played bit roles in Honey 2 and Step Up 3D and was a backup dancer for Beyonce at the 2010 Grammy Awards.

J. Lo and Smart are "nothing serious," this mole says, but adds they have been spending a lot of time together on New York City, attempting to remain incognito. But that can be difficult when you look like THIS.

[Photo: WENN.com]