OK! COVER STORY: Jennifer Aniston and Justin Theroux: A Baby at Last!

There is already space for a nursery in Jennifer Aniston’s $21 million Bel Air, Calif., mansion. It’s actually a two-room suite with a linking archway — and it will be styled by a celebrity designer who has a deeply personal stake in the finished product: Jen’s fiancé, Justin Theroux.

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“He shyly asked Jen if he could have a role in helping decorate the nursery — in addition to his role in helping make the actual baby, of course,” a close friend of the romantic comedy queen tells OK!. “Justin is such a natural artist, plus he’s free,” she joked, “so the job was his.”

First things first: The nursery needs an occupant; Jen has told friends that she and Justin are working on that — hard and fast. “It’s no secret she wanted a baby yesterday, so they’re not wasting any time,” another pal reveals. Justin, it seems, has had babies on the brain for quite a while.

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“The night he proposed he told Jen that he wanted her to have his child,” another pal reveals. “She was so happy and told all her girlfriends about it. Jen said it was one of the most beautiful and emotional moments ever. “When they were house hunting,” adds the pal, “Justin would regularly veto properties on the grounds that they weren’t child-friendly.”