Jen's pregnant and it's a boy!

Jennifer Aniston and Justin Theroux. Photo: Getty Images.

Jennifer Aniston and hubby Justin Theroux are pregnant with their first miracle baby - and it's all thanks to a very special boy in their life.

Sources confirm that Jen's one-year-old nephew Ryat is the inspiration behind Jen's latest desperate push to make hey baby dream come true, convincing her to become a mum.

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'Ryat is the light of Jen's life,' says an insider close to the actress. 'He's made her realise how important children are, she and Ryat have such a special bond.'

Since tying the knot at their Bel Air mansion in August, Jen, 46, and Justin, 44, have spent most of their time in New York, with Jen filming The Yellow Birds with Toni Collette and Justin working on The Leftovers - and both are 'completely overjoyed' to have a baby on the way.

'It's incredible news,' a close family pal tells New Idea.

'Everyone knows the years of disappointment Jen's gone through trying for a baby, and now she's saying it wasn't fertility treatment she needed, it was a husband!

'It's nothing short of a miracle for this to happen, and Jen's absolutely glowing with joy right now. She's convinced their baby is going to be a boy, because she keeps having crazy dreams about it.'

Another friends adds: 'Justin really wants a son!'

Family insiders tell New Idea the couple are desperately trying to keep their baby under wraps until she gets the green light from her doctor - but are privately celebrating their happy news with friends after a long wait to fall pregnant.

'Jen's put her body through hell trying for a baby with Justin,' the insider adds.

But it's Jen's newfound bond with her half-brother AJ - who is dad to little Ryat - which she believes helped make her baby dreams come true.

The siblings have been estranged for years, but put their differences aside after the birth of Ryat.

'Jen loves being an aunt,' says the source. 'Having little Ryat in her life has made her realise that she wants a baby with Justin more than anything.'

In the past Jen has spoken of the pressure she's felt to have a baby with her biological clock ticking fast. She recently told the US Today show: 'I don't have any sort of checklist of things that have to be done, and if they're not checked, then I've failed some part of my feminism, or my being a woman, or my worth and my value as a woman because I haven't birthed a child.

'I've birthed a lot of things and I feel like I've mothered many things. And I don't feel like it's fair to put that pressure on people.'

But now it looks like taking the pressure off and getting married has worked a treat for Jennifer and Justin.

'Neither of them can believe it's happened so easily and so quickly,' the pal says.

'Tying the knot did wonders for their relationship and threw all the insecurities out the window for good.'

As Jen said in her infamous post-Brad Vanity Fair interview in 2005: 'I've never in my life said I didn't want to have children. I did and I do and I will!'

'I've always wanted to have children, and I would never give up that experience for a career. I want to have it all.'

And with their baby dream coming true, pals reveal that Jen and Justin are busy thinking of names - and they have taken a liking to a few in particular.

'She and Justin are already picking out names for their little boy,' and insider tells Life & Style.

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'She likes names that are similar to Justin, so she's picked Preston, Ethan or Grayson.'

'She's hoping the boy will have Justin's dreamy hazel eyes.'