Jennifer Aniston is all smiles at the London premiere of Horrible Bosses.(Splash)

If all the reports of Jennifer Aniston being pregnant over the years were true, she would have a far bigger brood than her ex Brad Pitt, but could the 42-year-old finally be readying for motherhood with new boyfriend Justin Theroux?

While there's been no positive pregnancy test found in her garbage, there are certainly signs which give credence to the theory the overnight couple is preparing to become overnight parents.

We only just learned the "Wanderlust" co-stars were an official item last month but already their relationship appears to be moving at unusually fast speeds, especially considering Theroux's girlfriend of 14 years, Heidi Biven, just moved out of the apartment they shared in June.

You'd think Theroux would be easing into the high-profile relationship considering the suspicious timing and negative publicity around his breakup, but instead he's jumped head first into his role as Mr. Jennifer Aniston (and future co-parent to a kid with really great hair?).

Since their relationship became public the actor and "Tropic Thunder" writer hasn't left the A-lister's side, cheering her on during her Hand and Foot Print ceremony in L.A., sitting front and centre during her "Inside the Actors Studio" interview and even accompanying the star to London for the premiere of "Horrible Bosses" this week. There may very well be a reason beyond the rush of new love for his overly protective nature.

To those who argue Aniston's strict Greek upbringing would frown upon her welcoming a child out of wedlock, may we draw your attention to the couple's matching gold bands? The not-so-subtle signs of their commitment have been front and centre in all photographs of the duo for the past few weeks. There have also been reports Theroux has moved into Aniston's L.A. pad.

All this while the former "Friends" star reportedly plans to take an extended break from working to "enjoy herself." (Or maybe... attend pre-natal yoga classes?)

While jumping head first into a relationship is hardly a rarity in Hollywood and it certainly doesn't mean there's a baby involved, it's hard to deny there's something very different about Aniston these days. And it's not just the fact she's embracing white, flowery, feminine pieces in her wardrobe after years of sticking to LBDs.

She's also utterly radiant, almost bursting from the gills with happiness and there's not a hint of discretion, let alone shame you'd expect considering the "other woman" label she's been saddled with. Maybe it's easy to ignore your conscience when you're mentally planning a nursery?

Aniston famously told Oprah earlier this year she would be "so excited" when a child finally comes into her life that she would "scream it from the mountaintop."

Perhaps the couple's next trip together will be to the Andes...