Friends are worried that Natalie’s baby daddy and fiance might be using her for fame and fortune. Here’s why.

Natalie Portman has a lot going for her these days — Oscar buzz, a baby on board and a sexy fiance who adores her. Or does he? Friends of the actress aren’t really sure if Benjamin Millepied has the right intentions in mind. “They’re calling him the ballet version of K-Fed!” a pal of Natalie’s tells In Touch magazine. Sounds like we have another Kevin Federline and Britney Spears on our hands!

“He’s a self-promoter, who’s loving the spotlight,” the friend says of Benjamin, a principal dancer and choreographer at the New York City Ballet. “Her friends are worried she’s in over her head.” The couple fell hard for each other on the set of Black Swan, where Benjamin, 33, acted as Natalie’s dance partner and trained her for the ballet scenes. Interesting enough, the way Benjamin left his live-in girlfriend, American Ballet Theatre dancer Isabella Boylston, to be with Natalie is what sparked her friends’ concerns. “I don’t think he even thought twice about leaving his girlfriend — which isn’t a very good sign of character,” says the friend. “He seems like a social climber who was all over Natalie the moment they met.”

Back in 2004, when Britney, 29, started dating backup dancer, K-Fed, who left his then girlfriend Shar Jackson, everyone warned her that he was just using her for fame and fortune. But she didn’t listen. And now Kevin’s reaping the rewards of their two-year marriage — including alimony and child support payments for their two sons Sean,5, and Jayden, 4. Sounds a lot like what’s going on with Natalie now, doesn’t it?

Although we have never seen Natalie, 29, happier, we hope she isn’t rushing into things just because she’s expecting Benjamin’s child. “Unfortunately, he’s the father of her baby, and her pals think that she wouldn’t be getting married if she wasn’t pregnant, and that it’s all going too fast,” the friend reports. “They’re nervous that Natalie will wake up one day and wonder what happened.”

What do you think about Natalie and Benjamin? Does he have her best intentions in mind, or his?

–Leigh Blickley