Demi Moore Jealous Of Ashton Kutcher-Natalie Portman Flirts?

INFDaily.com.

Source says Demi Moore threatened by Ashton's co-star.

Ashton Kutcher is currently filming 2011's Friends with Benefits alongside the ever-striking Natalie Portman. Despite both Kutcher and Portman being involved in serious relationships (Kutcher, 32, is married to Demi Moore), it's said there may be some on-set chemistry happening...and Demi Moore doesn't like it.

We reported a few months ago that Natalie Portman had gotten serious with professional dancer/actor Benjamin Millepied. Since then she's been on-set in what appears to be Los Angeles with Ashton Kutcher filming Friends with Benefits, which has been described by insiders with the following: "A guy and girl try to keep their relationship strictly physical, but it's not long before they learn that they want something more."

While it all sounds like fun and games, there may be something more serious happening under the surface. An insider reports that Natalie Portman always has a way with men (we believe this to be true) and that at moments, it appears that Ashton Kutcher may be a bit smitten with her.

All this said, Demi Moore is operating with eyes in the back of her head, according to this latest report, from Us via Celebitchy: "Demi has never been jealous of Ashton's costars before, but she may be on to something this time. Three days after Ashton and Natalie filmed a steamy kissing scene, Ashton told Howard Stern that love scenes are like 'free cheating.' Though he was careful to add that he confessed everything to his wife because she's his 'best friend,' the insider says that Demi isn't as cool with it as she's letting him think."

The insider reportedly continued, "Natalie has had some on-set romances in the past ... She is in love with Ben, but Natalie has always had a way with men." In fact, it's said Portman digs Kutcher's personality: "Natalie loves his sense of humor and likes spending time with him," says the source.

How's Demi handling it? "Demi has told Ashton that she's visiting him on the set to get to know Natalie. But she's actually going to check up on him." In recent interviews, however, Kutcher has expressed his urgent desire to father Demi Moore's child, and both have reported that they are undergoing the necessary treatments for Demi to get pregnant. (If the treatments are successful, Moore will join John Travolta's wife Kelly Preston as a 47-year-old mom-to-be.)

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Stay with LimeLife for updates, and flip through our slideshow of happily married Demi Moore and Ashton Kutcher. In other celeb marital eyebrow-raisers, Jesse James is about to cry on TV over Sandra Bullock -- we're linking you through to the story and clip here.