Zoe Saldana welcomes third son with husband Marco Perego

Zoe Saldana and her husband have announced the birth of their baby boy.

The Avatar actress made the cute announcement on social media, with an adorable picture of her three sons playing.

As well as announcing the third addition to her brood, Zoe also revealed the name the couple chose for their youngest son - Zen.

'Marco and I are elated to share the news of the the birth of our son Zen. We couldn't feel more blessed with the new addition to our family. #threeboys... oh boy!', she captioned the picture.

The star likes to keep her private life away from the spotlight, and she managed to keep her pregnancy a complete surprise.

Zoe managed to keep her pregnancy a secret, choosing not to make an official announcement, and she hadn't been seen pregnant in public since expecting her twins in 2014.

This is Zoe's third son with husband Marco Perego, after they welcomed twins Cy and Bowie in December 2014.

The couple tied the knot in London just a year before, in 2013, in a secret ceremony in London, shortly after her relationship with Bradley Cooper came to an end.

Speaking about meeting Marco, the 38 year old said 'I met my partner when I was in really a beautiful place in my life,. It was like I found all my answers with him not in him. I was finding my answers on my own.'

Even though she announced the birth of her baby boy with a picture on social media, it's unlikely we will see any more of him anytime soon.

Apart from the occasional snaps she posts on social media, Zoe likes to keep her children anonymous and never shows their faces.

'It has to do with respecting who they are. They're too young to tell me how they would feel. They don't know if they're comfortable with that. It's too violating', she said'

'I can share them to the point that my husband and I are comfortable. I've never felt the impulse to show their faces. The trolling online is pretty disgraceful. I'm giving them a chance to have their own life.'

Congratulations to Zoe and Marco on the birth of their baby boy!