Zoe Saldana has dubbed the birth of her twins as the ''scariest day'' of her life.

The 39-year-old actress and her husband Marco Perego welcomed twin sons Bowie and Cy into the world three years ago, and whilst she believes the tots have been the ''light of her life'', she admits having two children to raise at once has been challenging.

Posting a picture of her brood on Instagram in honour of their birthday on Monday (27.11.17), the 'Guardians of the Galaxy' actress wrote: ''Happy Birthday Bowie and Cy! Today, November 27th will always be the happiest and scariest day of our lives. On a day like today, three years ago our lives changed forever. We went from being two to four in just 2 minutes. Even though your arrival was early and with a couple of scary hiccups you have been the light of our lives ever since we learned of your presence within us. Your strength, determination, curiosity and kindness humble us every day. Thank You for choosing us to guide you through the first stages of your purposeful path in life. You are both meant for greatness and by the grace of God your father and I will make sure you grow up to be exceptional men that will bring healing, wisdom, happiness, and change into this world. We have a big task ahead us, and that is to raise healthy, empathetic and selfless men. We hope to never let you down. And please continue to teach us how you need to be loved, seen, spoken to, taught, encouraged, protected- all the things you need to thrive and make your life meaningful.''

Zoe then repeated the message in Spanish, which is her husband's native language.

It comes after the 'Avatar' actress - who also has nine-month-old son Zen with her spouse - admitted her ''greatest wish'' is that her children don't grow up ''feeling conscious'' about the colour of their skin.

She said: ''My greatest wish for my kids is that they never grow up feeling conscious of the colour of their skin, or where their parents come from or that they can achieve anything in life.''