When Angelina Jolie dropped out of Alfonso Cuarón’s 3-D space movie Gravity, she likely had no idea what she'd wrought. Cuarón — who directed the racy Y Tu Mamá También and the Oscar-nominated Children of Men — quickly turned around and offered the part to Natalie Portman.

Jolie turned down the film citing a busy schedule due in part to her plans for an untitled Bosnian war romance film, which she is both writing and directing. Technically, this is not the actress’s first time in the director’s chair. She made her directorial debut with the 2007 documentary A Place In Time, though I’m hesitant to count this as I estimate that about 11.3 people saw the movie, half of which were Jolie's kids.

Could Portman replace Jolie in more ways than one?

She certainly has enough in common with her. In May 2011 Portman will star in Thor, based on the Marvel comic of the same name. The role sounds like many of Jolie’s: a sultry female lead in an action-fantasy-adventure. Both actresses are also ardent do-gooders: Portman traveled to Uganda, Guatemala, and Ecuador as the Ambassador of Hope for FINCA International and earned a nomination for Vh1’s 2010 Do Something Awards. Jolie, a United Nations refugees ambassador, recently provided hands-on help in Pakistani refugee camps and donated $1 million to relief efforts for the flood-ravaged nation.

The similarities continue. Jolie chose to birth her children in foreign countries and Portman has expressed desires to rear her offspring elsewhere, naming Israel a possibility. The two celebrities are even born under the same star: both are Geminis, ruled by planet Mercury, known for their intellectual prowess and lively spontaneity.

Plus Portman might even work alongside Jolie’s baby-daddy! Terrence Malick wants Portman for a role in a Jerry Lee Lewis biopic he is developing with Brad Pitt. Although Portman is currently dating French ballet dancer Benjamin Millepied, who choreographed her in Black Swan, who’s to say she won’t drop the Frenchie in favor of Pitt.

Remember — Brad is no stranger to on-set love stories, as evidenced from his budding romance with Jolie during the filming of 2005 Mr. and Mrs. Smith, an affair which ended his marriage to Jennifer Aniston.

Now not to get all Kennedy-Lincoln assassination on you (John Wilkes Booth shot from a theater and ran to a warehouse, Oswald shot from a warehouse and ran to a theater, etc...) but it is a convenient coincidence that Portman is exactly six years younger than Jolie, who's also six years younger than Aniston. Or consider this: Jolie, a doting mother to an ever-expanding brood, has transformed into a sort of American sweetheart the public can’t help but adore (consider Jennifer Aniston in Friends), while Portman’s love life remains shrouded in mystery as she seeks romances with French dancers and avant garde artists like Devendra Banhart.

I concede that this is all a bit far-fetched. After all, many attractive actresses fit the bill.

But why not Brad and Natalie? I, for one, am sick Brangelina’s alleged arguments dominating the tabloid covers. BORING. Besides, Angie’s string-bean limbs and pouty lips are so ‘'90s, and I really don’t understand her never-ending affinity for black. (Hey Angie: It’s DEPRESSING.)

What would we call Brad and Natalie? Natabrad? Brad-talie? Or what about Brattalie — the pair could sponsor a Bratz doll, cute! Imagine the feuding factions: Team Angie vs. Team Natalie.

Maybe Jolie would try to unite forces with Aniston… or even date Aniston as revenge (Jolie is bisexual, remember). Aniston seems desperate enough to fall for such a scheme.

At this point she’d be lucky if anyone on the A-list dated her for more than a month. (Not to be too harsh on the girl but I haven’t respected Aniston since she criticized John Mayer’s frequent twitter use. Twitter is a form of art, Jen, and until you realize and embrace the medium I’m going to hate you.)

Regardless of the outcome, Portman does pose a potential threat to Jolie, even if not to her relationship with Brad Pitt. If Gravity does well with Portman in the lead, there will be more than one bankable brunette in Hollywood.